History AdaptationInducedPlotHole / HarryPotter

** The Two-Way Mirror that Sirius gives to Harry in ''The Order of the Phoenix'' is left out of the film. This creates some rather glaring problems further down the line for the ''Deathly Hallows'' films. In the book, Harry ended up smashing the mirror in frustration after a failed attempt to use it to [[spoiler:contact Sirius beyond the grave]]. After this, Harry decides to save a shard of the smashed mirror as a keepsake. Meanwhile, due to [[spoiler:Sirius' death]], the other mirror ends up in the hands of Mundungus Fletcher, who ends up selling it to Dumbledore's brother, Aberforth. This leads to Harry observing a bright blue eye sometimes looking back at him from the shard, and due to the striking resemblance to Dumbledore's own eye, Harry ends up assuming that it is Dumbledore trying to [[spoiler:contact him from the afterlife]]. This is why Harry, when imprisoned in the cellar of Malfoy Manor, looks at the shard and begs for help. His plea for help is heard by Aberforth, who in response alerts Dobby, who then arrives to break Harry and the gang out. In the film, however, absolutely none of this context is given at any point, so to someone only familiar with the films, it comes across as Harry just suddenly and randomly taking a strange mirror shard out of his sock and begging it for help, resulting in it somehow summoning Dobby. While the second part of ''Hallows'' does make an attempt to patch over this hole -- by showing that the shard is a piece from a mirror found in Aberforth's house, and otherwise giving it a part of the book backstory of him having bought it off Fletcher -- this only makes the whole thing a minor VoodooShark, as it raises the question of why Aberforth would buy a broken mirror, and it still doesn't explain how Harry acquired the mirror shard, why he would keep the shard on his person, nor why he would feel compelled to call to it for help.

** In Oliver Wood's film explanation of Quidditch rules to Harry he says "You catch [the Golden Snitch], Potter, and we win." Catching the Snitch only awards 150 points and, while it is rare, it still possible to loose when catching the Snitch if the opposing team has a more than 150 point lead. Wood's book explanation, "Whichever Seeker catches the Snitch wins his team an extra hundred and fifty points, so they nearly always win," makes it far more understandable why the Keeper and Chaser positions even exist, while they are implied to be completely superfluous in the film.

* A minor one from ''Film/HarryPotterAndThePhilosophersStone'' is how the kids get caught out of bed. For some reason they decide to go to Hagrid's house at night despite finding out about the Philosopher's Stone during the day. They have no reason to sneak out, and why would Malfoy have any reason to follow them? Did he skulk around outside the Gryffindor common room waiting for them to make a move? It's just giving them one big IdiotBall so they can be caught and get sentenced to detention in the Forest. In [[Literature/HarryPotterAndThePhilosophersStone the book]], they were out of bed at night because they were trying to smuggle Hagrid's dragon (who had hatched weeks earlier) out of the school. Malfoy knew about this because he'd read a letter in Ron's book about the time and date of when they'd be going out to free the dragon.
* The Thestrals are explained as beings who can only seen by people who have experienced the death of someone firsthand. In the first book, Harry passes out before Quirrell dies, but in the film, Quirrell dies right in front of him, and yet Harry still can't see the Thestrals (which appear invisibly in ''Prisoner of Azkaban'', both the [[Literature/HarryPotterAndThePrisonerOfAzkaban book]] and [[Film/HarryPotterAndThePrisonerOfAzkaban movie]]) until after also seeing Cedric Diggory get murdered in [[Film/HarryPotterAndTheGobletOfFire the fourth film.]] For that matter, he might as well have been able to see them anyway, since both versions establish that he saw his mother die as a baby -- though that could be excused as he didn't know that to be so at the time.
* A minor one in the first movie comes during the flying lesson. In the book, Madam Hooch tells the students to start flying on the count of three; Neville, who's terrified of flying, accidentally jumps into the air on "two". In the movie, they're supposed to start flying when Madam Hooch blows her whistle, but when she does, Neville is the only one to start flying and everyone starts telling him to come down immediately.
* In ''Film/HarryPotterAndTheChamberOfSecrets'' after Harry finds the diary, as soon as he realises it can talk back, he immediately asks it about the Chamber, even though he would have no reason to suspect the diary is connected in any way to those events. A deleted scene shows (as in [[Literature/HarryPotterAndTheChamberOfSecrets the novel]]) a conversation the boys have with Hermione regarding the diary, where they make the connection. This scene was re-included in the extended version of the film.
* A much more baffling plot hole occurs immediately after Harry is shown the memory of [[spoiler:Hagrid being caught with Aragog]]. The very next scene is where the diary is stolen back. Harry meets nor speaks to anyone this entire time and no explanation is given later when it is revealed that [[spoiler:Ginny]] stole the diary back. In the novel, the Valentine's Day scene fills in this gap.
* In an [[InvertedTrope inversion]], on the other hand, Tom Riddle in the film tells Harry [[spoiler:that the Basilisk only obeys him and no other Parselmouths. The book shows no attempt on Harry's part to control the monster himself, nor does it try to explain why such wouldn't work.]]
* In the third film, after Harry falls off his broom in the Quidditch match against Hufflepuff. In the book (and the video game), Harry sees a black dog that he believes to be the Grim watching him from some empty seats. In the film, Harry inexplicably instead sees the outlines of the Grim appear in the sky. This would theoretically make sense if the Grim he had been spotting before was really a mystical omen of death and not [[spoiler:the Animagus form of Sirius Black, as we later find out]].
* The circumstances of Lupin preventing Harry from performing the Ridikkulus charm against the Boggart in the third film are changed, so that instead of stopping Harry before he confronts the Boggart, Lupin steps in after he has already seen it transform into a Dementor before Harry. In and of itself, this is a fair change from the book that helps indicate Lupin's desire to protect Harry ... but in a later scene, Lupin still tells Harry, as in the book, that he came between him and the Boggart because he feared it might take the form of Lord Voldemort, despite the fact that ''he clearly saw it transform into a Dementor''.
** Of course, it could have been argued Lupin had planned on doing it and hadn't been able to stop himself doing it, except that the scene has Harry in front of the boggart as a jack-in-the-box for a good long while before it transforms and Lupin steps in.
* The third movie never mentions who Moony, Wormtail, Padfoot, and Prongs are. This caused confusion among some audience members during the [[Film/HarryPotterAndTheOrderOfThePhoenix fifth movie]] when Harry wrote a letter to "Padfoot" without mentioning his given name, as well as Pettigrew being referred to exclusively as "Wormtail" in the fourth film. This also makes it a mystery how Lupin knows how the Map works.
* The ''Prisoner'' movie depicts the effects of the Disarming Charm, "Expelliarmus," inconsistently. When Lupin enters the Shrieking Shack, he uses it on Harry, removing his wand without causing him any harm, whereas when Harry casts the same spell on Snape minutes later, he is BlownAcrossTheRoom instead of disarmed. In the book, Harry, Ron, and Hermione used the spell at the same time and the combined effect threw Snape against the wall, but in the movie, Harry did it alone to the same effect.
* The sequence where the Map insults Snape is a bit weird. Snape catches Harry out of his dorm at night, which is enough to get him in trouble by itself. There's no reason for Snape to force Harry to empty his pockets, and no reason to suspect the map is anything but a blank piece of parchment.[[note]]Yes, Snape's a talented Legilimens, but again, Harry should be in trouble already; Snape doesn't need to look for more.[[/note]] After Lupin confiscates the Map, Harry somehow avoids further trouble. In the equivalent scene in the book, Snape catches Harry coming back from Hogsmeade, and has him empty his pockets and tries to reveal the Map's secret to prove Harry's been in Hogsmeade; when he can't, Harry barely escapes trouble.
* Krum has MindControlEyes while under the Imperius Curse in the fourth film. In the [[Film/HarryPotterAndTheDeathlyHallows seventh film]], the curse is portrayed more like in [[Literature/HarryPotterAndTheGobletOfFire the]] [[Literature/HarryPotterAndTheDeathlyHallows books]] wherein it appears: the Gringotts goblin just has a vacant smile. This could be {{Handwave}}[=d=] by the fact that Harry put the goblin under the curse, and he doesn't have as much experience at casting it, so he can't exert as much control on his targets as Crouch did.
* Averted by Creator/JKRowling herself, who stepped in after learning the fifth film would be cutting out the character Kreacher, and warned the crew that adapting book seven would be very problematic if he hadn't appeared before. However, so much of him was cut from ''Deathly Hallows – Part 1'' and completely cut from ''Part 2'' that they might as well have removed him completely.
* The films omit the entirety of Percy Weasley's minor-but-existent character arc, leaving it totally unexplained why he's suddenly working for [[ArcVillain Umbridge]] in the fifth movie, then just as suddenly back with the good guys in the finale.
* In ''[[Literature/HarryPotterAndTheOrderOfThePhoenix Order of the Phoenix]]'', the book, Hermione beginning to refer to Voldemort by his chosen name is a step forward for her in terms of CharacterDevelopment that gets Harry fully on board with deciding to start what becomes Dumbledore's Army. It's acknowledged in the book that this is the first time she has ever uttered the BigBad's name. In the first movie, however, she says the name unflinchingly: "Who was the one wizard Voldemort always feared?" And in the second film, when [[ArcVillain Lucius Malfoy]] mocks Harry for "be[ing] very brave, to say his name," she gets Dumbledore's line from the end of the first book, [[ShutUpHannibal "Fear of a name only increases fear of the thing itself."]] This softens the ''Phoenix'' moment's impact in the movies' continuity.
* In [[Literature/HarryPotterAndTheHalfBloodPrince the sixth book]], the Prime Minister and the (former) Minister for Magic briefly discuss a terrorist attack by Death Eaters against "the Brockdale Bridge," which killed several Muggles. [[Film/HarryPotterAndTheHalfBloodPrince The film]] shows the attack, setting it in London's famous Millennium Bridge ... [[AnachronismStew forgetting that the scene is supposed to take place in mid-1996, whereas construction on the real-life Millennium Bridge began in 1998 and it wasn't opened to the public until 2000.]]
* In the sixth film, Malfoy's entire year of planning is shown to be pointless at the end. The Death Eaters merely show up and stand there doing nothing, while in the book it was imperative that the Death Eaters enter Hogwarts in order to hold off all the members of the Order of the Phoenix guarding Hogwarts so Draco could finish his job (there would have been an amazing battle scene as a result). In the film, the battle doesn't happen and the Death Eaters just walk out.
* In the sixth film, Draco disarms Dumbledore. This is a key moment in the series that is revealed to be [[spoiler:the only part of Dumbledore's master plan that went wrong]], yet Dumbledore just lets himself be disarmed without defending himself. In the book, the only reason he was disarmed is because he sacrificed his chance to defend himself to immobilize Harry, who was wearing his invisibility cloak. Kind of makes Dumbledore seem like a total idiot.
* In ''Deathly Hallows Part 1'', Dobby tells Ron that it's nice to see him "again", despite the fact that in the continuity of the films, Dobby was never seen meeting Ron before this moment, having been AdaptedOut of films four through six (although it is possible they met off-screen).
* The final movie removes Dumbledore's explanation of why [[spoiler:Voldemort's Killing Curse in the forest failed to work on Harry]], leaving [[spoiler:his survival (and why it ''had'' to be Voldemort himself who cast the curse)]] a mystery with no "movie-canon" explanation. While it does explicitly explain why the [[spoiler:Elder Wand wouldn't work properly for Voldemort]] in the film (and [[spoiler:the failure of the Killing Curse]] could be explained simply by that), and Dumbledore also mentions that [[spoiler:Voldemort's SoulFragment]] is now gone (implying it might have served as PlotArmor), a question mark is still left behind on the completeness of the answer compared with the book's. (Then again, YMMV on whether or not adding [[spoiler:"And Voldemort's got your blood in him which means you're still protecting by your mother's sacrifice"]] really adds anything to the explanation: J.K. Rowling herself stated that [[spoiler:Harry's survival]] has as much to do with personal choice as the mechanics involved.
* The Two-Way Mirror that Sirius gives to Harry in ''The Order of the Phoenix'' is left out of the film. This creates some rather glaring problems further down the line for the ''Deathly Hallows'' films. In the book, Harry ended up smashing the mirror in frustration after a failed attempt to use it to [[spoiler:contact Sirius beyond the grave]]. After this, Harry decides to save a shard of the smashed mirror as a keepsake. Meanwhile, due to [[spoiler:Sirius' death]], the other mirror ends up in the hands of Mundungus Fletcher, who ends up selling it to Dumbledore's brother, Aberforth. This leads to Harry observing a bright blue eye sometimes looking back at him from the shard, and due to the striking resemblance to Dumbledore's own eye, Harry ends up assuming that it is Dumbledore trying to [[spoiler:contact him from the afterlife]]. This is why Harry, when imprisoned in the cellar of Malfoy Manor, looks at the shard and begs for help. His plea for help is heard by Aberforth, who in response alerts Dobby, who then arrives to break Harry and the gang out. In the film, however, absolutely none of this context is given at any point, so to someone only familiar with the films, it comes across as Harry just suddenly and randomly taking a strange mirror shard out of his sock and begging it for help, resulting in it somehow summoning Dobby. While the second part of ''Hallows'' does make an attempt to patch over this hole -- by showing that the shard is a piece from a mirror found in Aberforth's house, and otherwise giving it a part of the book backstory of him having bought it off Fletcher -- this only makes the whole thing a minor VoodooShark, as it raises the question of why Aberforth would buy a broken mirror, and it still doesn't explain how Harry acquired the mirror shard, why he would keep the shard on his person, nor why he would feel compelled to call to it for help.

* The third movie never mentions who Moony, Wormtail, Padfoot, and Prongs are. This caused confusion among some audience members during the [[Film/HarryPotterAndTheOrderOfThePhoenix fifth movie]] when Harry wrote a letter to "Padfoot" without mentioning his given name. Plus Pettigrew being referred to exclusively as "Wormtail" in the fourth film. And it's now a mystery how Lupin knows how the Map works.

* In ''Film/HarryPotterAndTheChamberOfSecrets'' after Harry finds the diary, as soon as he realises it can talk back he immediately asks it about the Chamber, even though he would have no reason to suspect the diary is connected in any way to those events. A deleted scene shows (as in [[Literature/HarryPotterAndTheChamberOfSecrets the novel]]) a conversation the boys have with Hermione regarding the diary.
* A much more baffling plot hole occurs immediately after: after Harry is shown the memory of [[spoiler:Hagrid being caught with Aragog]] the very next scene is where the diary is stolen back. Harry meets nor speaks to anyone this entire time and no explanation is given later when it is revealed that [[spoiler:Ginny]] stole the diary back. In the novel, the Valentine's Day scene fills in this gap.

* The Thestrals are explained as beings who can only seen by people who has experienced the death of someone firsthand. In the first book, Harry passes out before Quirrell dies, but in the film, Quirrell dies right in front of him, and yet Harry still can't see the Thestrals (which appear invisibly in ''Prisoner of Azkaban'', both the [[Literature/HarryPotterAndThePrisonerOfAzkaban book]] and [[Film/HarryPotterAndThePrisonerOfAzkaban movie]]) until after also seeing Cedric Diggory get murdered in [[Film/HarryPotterAndTheGobletOfFire the fourth film.]]

* A much more baffling plot hole occurs immediately after, after Harry is shown the memory of [[spoiler:Hagrid being caught with Aragog]] the very next scene is where the diary is stolen back. Harry meets nor speaks to anyone this entire time and no explanation is given later when it is revealed that [[spoiler:Ginny]] stole the diary back. In the novel, the Valentine's Day scene fills in this gap.
* In an [[InvertedTrope inversion]], on the other hand, Tom Riddle in the film tells Harry [[spoiler:that the Basilisk only obeys him and no other Parselmouths. The book shows no attempt on Harry's part to control the monster himself, nor does it try to explain why it wouldn't work.]]
* In the third film, after Harry falls off his broom in the Quidditch match. In the book (and the video game), Harry sees a black dog that he believes to be the Grim watching him from some empty seats. In the film, Harry inexplicably instead sees the outlines of the Grim appear in the sky. This would theoretically make sense if the Grim he had been spotting before was really a mystical omen of death and not [[spoiler:the Animagus form of Sirius Black, as we later find out]].

* The ''Prisoner'' movie is inconsistent with the effects of the Disarming Charm, "Expelliarmus." When Lupin enters the Shrieking Shack, he uses it on Harry, removing his wand without causing him any harm, whereas when Harry casts the same spell on Snape minutes later, he is BlownAcrossTheRoom instead of disarmed. In the book, Harry, Ron, and Hermione used the spell at the same time and the combined effect threw Snape against the wall, but in the movie, Harry did it alone to the same effect.
* The sequence where the Map insults Snape is a bit weird. Snape catches Harry out of his dorm at night, which is enough to get him in trouble by itself. There's no reason for Snape to force Harry to empty his pockets, and no reason to suspect the map is anything but a blank parchment.[[note]]Yes, Snape's a talented Legilimens, but again, Harry should be in trouble already; Snape doesn't need to look for more.[[/note]] After Lupin confiscates the Map, Harry somehow avoids further trouble. In the equivalent scene in the book, Snape catches Harry coming back from Hogsmeade, and has him empty his pockets and tries to reveal the Map's secret to prove Harry's been in Hogsmeade; when he can't, Harry barely escapes trouble.
* Krum has MindControlEyes while under the Imperius Curse in the fourth film. In the [[Film/HarryPotterAndTheDeathlyHallows seventh film]], the curse is portrayed more like in [[Literature/HarryPotterAndTheGobletOfFire the]] [[Literature/HarryPotterAndTheDeathlyHallows books]] wherein it appears: the Gringotts goblin just has a vacant smile. This could be {{Handwave}}[=d=] by the fact that it was Harry who put the goblin under the curse, and he doesn't have as much experience at casting it, so he can't exert as much control on his targets as Crouch did.

* In ''Order of the Phoenix'', the book, Hermione beginning to refer to Voldemort by his chosen name is a step forward for her in terms of CharacterDevelopment that gets Harry fully on board with deciding to start what becomes Dumbledore's Army. It's acknowledged in the book that this is the first time she has ever uttered the BigBad's name. In the first movie, however, she says the name unflinchingly: "Who was the one wizard Voldemort always feared?" And in the second film, when [[ArcVillain Lucius Malfoy]] mocks Harry for "be[ing] very brave, to say his name," she gets Dumbledore's line from the end of the first book, [[ShutUpHannibal "Fear of a name only increases fear of the thing itself."]] This softens the ''Phoenix'' moment's impact in the movies' continuity.
* In [[Literature/HarryPotterAndTheHalfBloodPrince the sixth book]], the Prime Minister and the (former) Minister for Magic briefly discuss a terrorist attack by Death Eaters against an unnamed bridge that kills several Muggles. [[Film/HarryPotterAndTheHalfBloodPrince The film]] actually shows the attack, setting it in London's famous Millennium Bridge ... [[AnachronismStew forgetting that the scene is supposed to take place in mid-1996, whereas construction on the real-life Millennium Bridge began in 1998 and it wasn't opened to the public until 2000.]]

* In ''Deathly Hallows - Part 1'', Dobby tells Ron that it's nice to see him "again", despite the fact that in the continuity of the films, Dobby was never seen meeting Ron before this moment (although it is possible they met off-screen).

* The Two-Way Mirror that Sirius gives to Harry in ''The Order of the Phoenix'' is left out of the film. This creates some rather glaring problems further down the line for the ''Deathly Hallows'' films. In the book, Harry ended up smashing the mirror in frustration after a failed attempt to use it to [[spoiler:contact Sirius beyond the grave]]. After this, Harry decides to save a shard of the smashed mirror as a keepsake. Meanwhile, due to [[spoiler:Sirius' death]], the other mirror ends up in the hands of Mundungus Fletcher, who ends up selling it Dumbledore's brother, Aberforth. This leads to Harry observing a bright blue eye sometimes looking back at him from the shard, and due to the striking resemblance to Dumbledore's own eye, Harry ends up assuming that it is Dumbledore trying to [[spoiler:contact him from the afterlife]]. This is why Harry, when imprisoned in the cellar of Malfoy Manor, looks at the shard and begs for help. His plea for help is heard by Aberforth, who in response alerts Dobby, who then arrives to break Harry and the gang out. In the film, however, absolutely none of this context is given at any point, so to someone only familiar with the films, it comes across as Harry just suddenly and randomly taking a strange mirror shard out of his sock and begging it for help, resulting in it somehow summoning Dobby. While the second part of ''Hallows'' does make an attempt to patch over this hole -- by showing that the shard is a piece from a mirror found in Aberforth's house, and otherwise giving it a part of the book backstory of him having bought it off Fletcher -- this only makes the whole thing a minor VoodooShark, as it raises the question of why Aberforth would buy a broken mirror, and it still doesn't explain how Harry acquired the mirror shard, why he would keep the shard on his person, nor why he would feel compelled to call to it for help.
* The movies can't decide if Hogwarts students are allowed to use magic outside of school or not. Three of the books have Harry getting caught or blamed for using magic at home. As well as these events, the second movie has the rule-abiding Hermione magically fix Harry's glasses in public in front of several adult wizards and the third starts with Harry practicing spells in his bedroom as part of his summer homework.

* A minor one from ''Film/HarryPotterAndThePhilosophersStone'' is how the kids get caught out of bed. For some reason they decide to go to Hagrid's house at night despite finding out about the Philosopher's Stone during the day. They have no reason to sneak out, and why would Malfoy have any reason to follow them? Does he skulk around outside the Gryffindor common room waiting for them to make a move? It's just giving them one big IdiotBall so they can be caught and have to do detention in the forest. In the book, they were out of bed at night because they were trying to smuggle Hagrid's dragon (who had hatched weeks earlier) out of the school. Malfoy knew about this because he'd read a letter in Ron's book about the time and date of when they'd be out and about to get rid of the dragon.
* The Thestrals are explained as beings who can only seen by people who has experienced the death of someone first-hand. In the first book, Harry passes out before Quirrell dies, but in the film, Quirrell dies right in front of him, and yet Harry still can't see the Thestrals (which appear invisibly in ''Prisoner of Azkaban'') until after also seeing Cedric Diggory get murdered in the fourth film.

* In ''Film/HarryPotterAndTheChamberOfSecrets'' after Harry finds the diary, as soon as he realises it can talk back he immediately asks it about the Chamber, even though he would have no reason to suspect the diary is connected in any way to those events. A deleted scene shows (as in the novel) a conversation the boys have with Hermione regarding the diary.

* In an [[InvertedTrope inversion]] on the other hand, Tom Riddle in the film tells Harry [[spoiler:that the Basilisk only obeys him and no other Parselmouths. The book shows no attempt on Harry's part to control the monster himself, nor does it give any explanation as to why it wouldn't work.]]

* The circumstances of Lupin preventing Harry from performing the Ridikkulus charm against the Boggart in the third film are changed, so that instead of stopping Harry before he confronts the Boggart, Lupin steps in after he has already seen it transform into a Dementor before Harry. In and of itself, this is a fair change from the book that helps indicate Lupin's desire to protect Harry... but in a later scene, Lupin still tells Harry, as in the book, that he came between him and the Boggart because he feared it might take the form of Lord Voldemort, despite the fact that ''he clearly saw it transform into a Dementor''.
* The third movie never mentions who Moony, Wormtail, Padfoot, and Prongs are. This caused confusion among some audience members during the fifth movie when Harry wrote a letter to "Padfoot" without mentioning his given name. Plus Pettigrew being referred to exclusively as "Wormtail" in the fourth film. And it's now a mystery how Lupin knows how the map works.
* The same movie is inconsistent with effects of "expeliarmus" spell. When Lupin entered Shrieking Shack he used it on Harry which removed his wand without causing him any harm, while the same spell used by Harry on Snape had him BlownAcrossTheRoom instead of disarming him. In the book Harry, Ron and Hermione used the spell at the same time and it was combined effect which threw Snape on the wall, but in the movie Harry did it alone to the same effect.
* The sequence where the Map insults Snape is a bit weird. Snape catches Harry out of his dorm at night, which is enough to get him in trouble by itself. There's no reason for Snape to force Harry to empty his pockets, and no reason to suspect the map is anything but a blank parchment[[note]]Yes, Snape's a talented Legilimens, but again, Harry should be in trouble already; Snape doesn't need to look for more.[[/note]]. After Lupin confiscates the map, Harry somehow avoids further trouble. In the book, Snape catches Harry coming back from Hogsmeade, and has him empty his pockets and tries to reveal the Map's secret to prove Harry's been in Hogsmeade; when he can't, Harry barely escapes trouble.
* Krum has MindControlEyes while under the Imperius Curse in the fourth film. In the seventh film, the curse is portrayed more like in the book; the Gringotts goblin just has a vacant smile. This could be {{Handwave}}'d by the fact that it was Harry who put the goblin under the curse, and he doesn't have as much experience at casting it, so it can't exert as much control on someone as Crouch did.
* Averted by J.K. Rowling herself, who stepped in after learning the fifth film would be cutting out the character Kreacher, and warned the crew that adapting book seven would be very problematic if he hadn't appeared before. However, so much of him was cut from ''Deathly Hallows – Part 1'' and completely cut from ''Part 2'' that they might as well have removed him completely.
* The films omit the entirety of Percy Wesley's minor-but-existent character arc, leaving it totally unexplained why he's suddenly working for [[ArcVillain Umbridge]] in the fifth movie, then just as suddenly back with the good guys in the finale.
* In the sixth book, the Prime Minister and the Minister for Magic briefly discuss a terrorist attack by Death Eaters against an unnamed bridge that kills several Muggles. The film actually shows the attack, setting it in London's famous Millennium Bridge... forgetting that the scene is supposed to take place in mid-1997, whereas construction on the real-life Millennium Bridge began in 1998 and it wasn't opened to the public until 2000.
* In the sixth film, Malfoy's entire year of planning is shown to be pointless at the end of the film. The Death Eaters merely show up and stand there doing nothing, while in the book it was imperative that the Death Eaters enter Hogwarts in order to hold off all the members of the Order of the Phoenix guarding Hogwarts so Draco could finish his job (there would have been an amazing battle scene as a result). In the film, the battle doesn't happen and the Death Eaters just walk out.

* The final movie removes Dumbledore's explanation of why [[spoiler:Voldemort's Killing Curse in the forest failed to work on Harry]], leaving [[spoiler:his survival (and why it ''had'' to be Voldemort himself who cast the curse)]] a mystery with no "movie-canon" explanation. While it does explicitly explain why the [[spoiler:Elder Wand wouldn't work properly for Voldemort]] in the film (and [[spoiler:the failure of the Killing Curse]] could be explained simply by that), and Dumbledore also mentions that [[spoiler:Voldemort's SoulFragment]] is now gone (implying it might have served as PlotArmor), a question mark is still left behind on the completeness of the answer compared with the book's. (Then again, YMMV on whether or not adding [[spoiler: "And Voldemort's got your blood in him which means you're still protecting by your mother's sacrifice"]] really adds anything to the explanation: J.K. Rowling herself stated that [[spoiler: Harry's survival]] has as much to do with personal choice as the mechanics involved.
* The Two-Way Mirror that Sirus gives to Harry in ''The Order of the Phoenix'' is left out of the film. This creates some rather glaring problems further down the line for the ''Deathly Hallows'' films. In the book, Harry ended up smashing the mirror in frustration after a failed attempt to use it to [[spoiler:contact Sirus beyond the grave]]. After this, Harry decides to save a shard of the smashed mirror as a keepsake. Meanwhile, due to [[spoiler:Sirus' death]], the other mirror ends up in the hands of Mundungus Fletcher, who ends up selling it Dumbledore's brother, Aberforth. This leads to Harry observing a bright blue eye sometimes looking back at him from the shard, and due to the striking resemblance to Dumbledore's own eye, Harry ends up assuming that it is Dumbledore trying to [[spoiler:contact him from the afterlife]]. This is why Harry, when imprisoned in the cellar of Bellatrix Lestrange's manor, looks at the shard and begs for help. His plea for help is heard by Aberforth, who in response alerts Dobby, who then arrives to break Harry and the gang out. In the film, however, absolutely none of this context is given at any point, so to someone only familiar with the films, it comes across as Harry just suddenly and randomly taking a strange mirror shard out of his sock and begging it for help, resulting in it somehow summoning Dobby. While the second part of ''Hallows'' does make an attempt to patch over this hole -- by showing that the shard is a piece from a mirror found in Aberforth's house, and otherwise giving it a part of the book backstory of him having bought it off Fletcher -- but this only accomplishes making the whole thing into a bit of a VoodooShark, as it begs the question of why Aberforth would buy a broken mirror, and it still doesn't explain how Harry acquired the mirror shard, why would he keep the shard on his person, nor why he would feel compelled to call to it for help.

* In the first book, Harry passes out before Quirrell dies, but in the film, Quirrell dies right in front of him, and yet Harry still can't see the Thestrals (which appear invisibly in ''Prisoner of Azkaban'') until after also seeing Cedric Diggory get murdered in the fourth film.

* The Two-Way Mirror that Sirus gives to Harry in ''The Order of the Phoenix'' is left out of the film. This creates some rather glaring problems further down the line for the ''Deathly Hallows'' films. In the book, Harry ended up smashing the mirror in frustration after a failed attempt to use it to [[spoiler:contact Sirus beyond the grave]]. After this, Harry decides to save a shard of the smashed mirror as a keepsake. Meanwhile, due to [[spoiler:Sirus' death]], the other mirror ends up in the hands of Mundungus Fletcher, who ends up selling it Dumbledore's brother, Aberforth. This leads to Harry observing a bright blue eye sometimes looking back at him from the shard, and due to the striking resemblance to Dumbledore's own eye, Harry ends up assuming that it is Dumbledore trying to [[spoiler:contact him from the afterlife]]. This is why Harry, when imprisoned in the cellar of Bellatrix Lestrange's manor, looks at the shard and begs for help. His plea for help is heard by Aberforth, who in response alerts Dobby, who then arrives to break them out. In the film, however, absolutely none of this context is given at any point, so to someone only familiar with the films, it comes across as Harry just suddenly and randomly taking a strange mirror shard out of his sock and begging it for help, resulting in it somehow summoning Dobby. While the second part of ''Hallows'' does make an attempt to patch over this hole -- by showing that the shard is a piece from a mirror found in Aberforth's house, and otherwise giving it a part of the book backstory of him having bought it off Fletcher -- but this only accomplishes making the whole thing into a bit of a VoodooShark, as it begs the question of why Aberforth would buy a broken mirror, and it still doesn't explain how Harry acquired the mirror shard, why would he keep the shard on his person, nor why he would feel compelled to call to it for help.

* The Two-Way Mirror that Sirus gives to Harry in ''The Order of the Phoenix'' is left out of the film. This creates some rather glaring problems further down the line for the ''Deathly Hallows'' films. In the book, Harry ended up smashing the mirror in frustration after a failed attempt to use it to [[spoiler:contact Sirus beyond the grave]]. After this, Harry decides to save a shard as a keepsake. Meanwhile, due to [[spoiler:Sirus' death]], the other mirror ends up in the hands of Mundungus Fletcher, who ends up selling it Dumbledore's brother, Aberforth. This leads to Harry observing a bright blue eye sometimes looking back at him from the shard, and due to the striking resemblance to Dumbledore's own eye, Harry ends up assuming that it is Dumbledore trying to [[spoiler:contact him from the afterlife]]. This is why Harry, when imprisoned in the cellar of Bellatrix Lestrange's manor, looks at the shard and begs for help. His plea for help is heard by Aberforth, who in response alerts Dobby, who then arrives to break them out. In the film, however, absolutely none of this context is given at any point, so to someone only familiar with the films, it comes across as Harry just suddenly and randomly taking a strange mirror shard out of his sock and begging it for help, resulting in it somehow summoning Dobby. While the second part of ''Hallows'' does make an attempt to patch over this hole -- by showing that the shard is a piece from a mirror found in Aberforth's house, and otherwise giving it a part of the book backstory of him having bought it off Fletcher -- but this only accomplishes making the whole thing into a bit of a VoodooShark, as it begs the question of why Aberforth would buy a broken mirror, and it still doesn't explain how Harry acquired the mirror shard, why would he keep the shard on his person, nor why he would feel compelled to call to it for help.

* The movies can't decide if Hogwarts students are allowed to use magic outside of school. Three of the books have Harry getting caught or blamed for using magic at home. As well as these events, the second movie has the rule-abiding Hermione magically fix Harry's glasses in public in front of several adult wizards and the third starts with Harry practicing spells in his bedroom as part of his summer homework.

* The Two-Way Mirror that Sirus gives to Harry in ''The Order of the Phoenix'' is left out of the film. This creates some rather glaring problems further down the line for the ''Deathly Hallows'' films. In the book, Harry ended up smashing the mirror in frustration after a failed attempt to use it to [[spoiler:contact Sirus beyond the grave]]. After this, Harry decides to save a shard as a keepsake. Meanwhile, due to [[spoiler:Sirus' death]], the other mirror ends up in the hands of Mundungus Fletcher, who ends up selling it Dumbledore's brother, Aberforth. This leads to Harry observing a bright blue eye sometimes looking back at him from the shard, and due to the striking resemblance to Dumbledore's own eye, Harry ends up assuming that it is Dumbledore trying to [[spoiler:contact him from the afterlife]]. This is why Harry, when imprisoned in the cellar of Bellatrix Lestrange's manor, looks at the shard and begs for help. His plea for help is heard by Aberforth, who in response alerts Dobby, who then arrives to break them out. In the film, however, absolutely none of this context is given at any point, so to someone only familiar with the films, it comes across as Harry just suddenly and randomly taking a strange mirror shard out of his sock and begging it for help, resulting in it somehow summoning Dobby. While the second part of ''Hallows'' does make an attempt to patch over this hole -- by showing that the shard is a piece from a mirror found in Aberforth's house, and otherwise giving it a part of the book backstory of him having bought it off Fletcher -- but this only accomplishes making the whole thing into a bit of a VoodooShark, as it begs the question of why Aberforth would buy a broken mirror, and it still doesn't explain why Harry would keep the shard on his person nor why he would feel compelled to call to it for help.

* The Two-Way Mirror that Sirus gives to Harry in ''The Order of the Phoenix'' is left out of the film. This creates some rather glaring problems further down the line for the ''Deathly Hallows'' films. In the book, Harry ended up smashing the mirror in frustration after a failed attempt to use it to [[spoiler:contact Sirus beyond the grave]]. After this, Harry decides to save a shard as a keepsake. Meanwhile, due to [[spoiler:Sirus' death]], the other mirror ends up in the hands of Mundungus Fletcher, who ends up selling it Dumbledore's brother, Aberforth. This leads to Harry observing a bright blue eye sometimes looking back at him from the shard, and due to the striking resemblance to Dumbledore's own eye, Harry ends up assuming that it is Dumbledore trying to [[spoiler:contact him from the afterlife]]. This is why Harry, when imprisoned in the cellar of Bellatrix Lestrange's manor, looks at the shard and begs for help. His plea for help is heard by Aberforth, who in response alerts Dobby, who then arrives to break them out. In the film, however, absolutely none of this context is given at any point, so to someone only familiar with the films, it comes across as Harry just suddenly and randomly taking a strange mirror shard out of his sock and begging it for help, resulting in it somehow summoning Dobby. While the second part of ''Hallows'' does make an attempt to patch over this hole -- by showing that the shard is a piece from a mirror found in Aberforth's house, and otherwise giving it a part of the book backstory of him having bought it off Fletcher -- but this only accomplishes making the whole thing into a bit of a VoodooShark, as it begs the question of why Aberforth would buy a broken mirror, and it still doesn't explain why Harry ended up with a shard from it in his sock.

* The Two-Way Mirror that Sirus gives to Harry in ''The Order of the Phoenix'' is left out of the film. This creates some rather glaring problems further down the line for the ''Deathly Hallows'' films. In the book, Harry ended up smashing the mirror in frustration after a failed attempt to use it to [[spoiler:contact Sirus beyond the grave]]. After this, Harry decides to save a shard as a keepsake. Meanwhile, due to [[spoiler:Sirus' death]], the other mirror ends up in the hands of Mundungus Fletcher, who ends up selling it Dumbledore's brother, Aberforth. This leads to Harry observing a bright blue eye sometimes looking back at him from the shard, and due to the striking resemblance to Dumbledore's own eye, Harry ends up assuming that it is Dumbledore trying to [[spoiler:contact him from the afterlife]]. This is why Harry, when imprisoned in the cellar of Bellatrix Lestrange's manor, looks at the shard and begs for help. His plea for help is heard by Aberforth, who in response sends Dobby to get break them out. In the film, however, absolutely none of this context is given at any point, so to someone only familiar with the films, it comes across as Harry just suddenly and randomly taking a strange mirror shard out of his sock and begging it for help, resulting in it somehow summoning Dobby. While the second part of ''Hallows'' does make an attempt to patch over this hole -- by showing that the shard is a piece from a mirror found in Aberforth's house, and otherwise giving it a part of the book backstory of him having bought it off Fletcher -- but this only accomplishes making the whole thing into a bit of a VoodooShark, as it begs the question of why Aberforth would buy a broken mirror, and it still doesn't explain why Harry ended up with a shard from it in his sock.

* The Two-Way Mirror that Sirus gives to Harry in ''The Order of the Phoenix'' is left out of the film. This creates some rather glaring problems further down the line for the ''Deathly Hallows'' films. In the book, Harry ended up smashing the mirror in frustration after a failed attempt to use it to [[spoiler:contact Sirus beyond the grave]]. After this, Harry decides to save a shard as a keepsake. Meanwhile, due to [[spoiler:Sirus' death]], the other mirror ends up in the hands of Mundungus Fletcher, who ends up selling it Dumbledore's brother, Aberforth. This leads to Harry observing a bright blue eye sometimes looking back at him from the shard, and due to the striking resemblance to Dumbledore's own eye, Harry ends up assuming that it is Dumbledore trying to [[spoiler:contact him from the afterlife]]. This why Harry, when imprisoned in the cellar of Bellatrix Lestrange's manor, looks at the shard and begs for help. His plea for help is heard by Aberforth, who in response sends Dobby to get break them out. In the film, however, absolutely none of this context is given at any point, so to someone only familiar with the films, it comes across as Harry just suddenly and randomly taking a strange mirror shard out of his sock and begging it for help, resulting in it somehow summoning Dobby. While the second part of ''Hallows'' does make an attempt to patch over this hole -- by showing that the shard is a piece from a mirror found in Aberforth's house, and otherwise giving it a part of the book backstory of him having bought it off Fletcher -- but this only accomplishes making the whole thing into a bit of a VoodooShark, as it begs the question of why Aberforth would buy a broken mirror, and it still doesn't explain why Harry ended up with a shard from it in his sock.

* The Two-Way Mirror that Sirus gives to Harry in ''The Order of the Phoenix'' is left out of the film. This creates some rather glaring problems further down the line for the ''Deathly Hallows'' film. In the book, Harry ended up smashing the mirror in frustration after a failed attempt to use it to [[spoiler:contact Sirus beyond the grave]]. After this, Harry decides to save a shard as a keepsake. Meanwhile, due to [[spoiler:Sirus' death]], the other mirror ends up in the hands of Mundungus Fletcher, who ends up selling it Dumbledore's brother, Aberforth. This leads to Harry observing a bright blue eye sometimes looking back at him from the shard, and due to the striking resemblance to Dumbledore's own eye, Harry ends up assuming that it is Dumbledore trying to [[spoiler:contact him from the afterlife]]. This why Harry, when imprisoned in the cellar of Bellatrix Lestrange's manor, looks at the shard and begs for help. His plea for help is heard by Aberforth, who in response sends Dobby to get break them out. In the film, however, absolutely none of this context is given at any point, so to someone only familiar with the films, it comes across as Harry just suddenly and randomly taking a strange mirror shard out of his sock and begging it for help, resulting in it somehow summoning Dobby. While the second part of ''Hallows'' does make an attempt to patch over this hole -- by showing that the shard is a piece from a mirror found in Aberforth's house, and otherwise giving it a part of the book backstory of him having bought it off Fletcher -- but this only accomplishes making the whole thing into a bit of a VoodooShark, as it begs the question of why Aberforth would buy a broken mirror, and it still doesn't explain why Harry ended up with a shard from it in his sock.

* The Two-Way Mirror that Sirus gives to Harry in ''The Order of the Phoenix'' is left out of the film. This creates some rather glaring problems further down the lines for the ''Deathly Hallows'' film. In the book, Harry ended up smashing the mirror in frustration after a last ditch attempt to use it to [[spoiler:contact Sirus beyond the grave]]. After this, Harry decides to save a shard as a keepsake. Meanwhile, due to [[spoiler:Sirus' death]], the other mirror ends up in the hands of Mundungus Fletcher, who ends up selling it Dumbledore's brother, Aberforth. This leads to Harry observing a bright blue eye sometimes looking back at him from the shard, and due to the striking resemblance to Dumbledore's own eye, Harry ends up assuming that it is Dumbledore trying to [[spoiler:contact him from the afterlife]]. This why Harry, when imprisoned in the cellar of Bellatrix Lestrange's manor, looks at the shard and begs for help. His plea for help is heard by Aberforth, who in response sends Dobby to get break them out. In the film, however, absolutely none of this context is given at any point, so to someone only familiar with the films, it comes across as Harry just suddenly and randomly taking a strange mirror shard out of his sock and begging it for help, resulting in it somehow summoning Dobby. While the second part of ''Hallows'' does make an attempt to patch over this hole -- by showing that the shard is a piece from a mirror found in Aberforth's house, and otherwise giving it a part of the book backstory of him having bought it off Fletcher -- but this only accomplishes making the whole thing into a bit of a VoodooShark, as it begs the question of why Aberforth would buy a broken mirror, and it still doesn't explain why Harry ended up with a shard from it in his sock.

* The Two-Way Mirror that Sirus gives to Harry in ''The Order of the Phoenix'' is left out of the film. This creates some rather glaring problems further down the lines for the ''Deathly Hallows'' film. In the book, Harry ended up smashing the mirror in frustration after a last ditch attempt to use it to [[spoiler:contact Sirus beyond the grave]]. After this, Harry decides to save a shard as a keepsake. Meanwhile, due to [[spoiler:Sirus' death]], the other mirror ends up in the hands of Mundungus Fletcher, who ends up selling it Dumbledore's brother, Aberforth. This leads to Harry observing a bright blue eye sometimes looking back at him from the shard, and due to the striking resemblance to Dumbledore's own eye, Harry ends up assuming that it is Dumbledore trying to [[spoiler:contact him from the afterlife]]. This why Harry, when imprisoned in the cellar of Bellatrix Lestrange's manor, looks at the shard and begs for help. His plea for help is heard by Aberforth, who in response sends Dobby to get break them out. In the film, however, absolutely none of this context is given at any point, so to someone only familiar with the films, it comes across as Harry just suddenly and randomly taking a strange mirror shard out of his sock and begging it for help, resulting in it somehow summoning Dobby. While the second part of ''Hallows'' does make an attempt to patch over this hole -- by showing that the shard is a piece from a mirror found in Aberforth's house, and otherwise giving it a part of the book backstory of him having bought it off Fletcher -- but this only accomplishes making the whole thing into a bit of a VoodooShark, as it begs the question of why Aberforth would by a broken mirror, and it still doesn't explain why Harry ended up with a shard from it in his sock.

* The Two-Way Mirror that Sirus gives to Harry in ''The Order of the Phoenix'' is left out of the film. This creates some rather glaring problems further down the lines for the ''Deathly Hallows'' film. In the book, Harry ended up smashing the mirror in frustration after a last ditch attempt to use it to [[spoiler:contact Sirus beyond the grave]]. After this, Harry decides to save a shard as a keepsake. Meanwhile, due to [[spoiler:Sirus' death]], the other mirror ends up in the hands of Mundungus Fletcher, who ends up selling it Dumbledore's brother, Aberforth. This leads to Harry observing a bright blue eye sometimes looking back at him from the shard, and due to the striking resemblance to Dumbledore's own eye, Harry ends up assuming that it is Dumbledore trying to [[spoiler:contact him from the afterlife]]. This why Harry, when imprisoned in the cellar of Bellatrix Lestrange's manor, looks at the shard and begs for help. His plea for help is heard by Aberforth, who in response sends Dobby to get break them out. In the film, however, absolutely none of this context is given at any point, so to someone only familiar with the films, it comes across as Harry just suddenly and randomly taking a strange mirror shard out of his sock and begging it for help, resulting in it somehow summoning Dobby. While the second part of ''Hallows'' does make an attempt to patch over this hole -- by showing that the shard is a piece from a mirror found in Aberforth's house, and otherwise giving it a part of the book backstory of him having bought it from Mundungus Fletcher -- but this only accomplishes making the whole thing into a bit of a VoodooShark, as it begs the question of why Aberforth would by a broken mirror, and it still doesn't explain why Harry ended up with a shard from it in his sock.

* The Two-Way Mirror that Sirus gives to Harry in ''The Order of the Phoenix'' is left out of the film. This creates some rather glaring problems further down the lines for the ''Deathly Hallows'' film. In the book, Harry ended up smashing the mirror in frustration after a last ditch attempt to use it to [[spoiler:contact Sirus beyond the grave]]. After this, Harry decides to save a shard as a keepsake. Meanwhile, due to [[spoiler:Sirus' death]], the other mirror ends up in the hands of Mundungus Fletcher, who ends up selling it Dumbledore's brother, Aberforth. This leads to Harry observing a bright blue eye sometimes looking back at him from the shard, and due to the striking resemblance to Dumbledore's own eye, Harry ends up assuming that it is Dumbledore trying to [[spoiler:contact him from the afterlife]]. This why Harry, when imprisoned in the cellar of Bellatrix Lestrange's manor, looks at the shard and begs for help. His plea for help is heard by Aberforth, who in response sends Dobby to get break them out. In the film, however, absolutely none of this context is given at any point, so to someone only familiar with the films, it comes across as Harry just suddenly and randomly taking a strange mirror shard out of his sock and begging it for help, resulting in it somehow summoning Dobby. While the second part of ''Hallows'' does make an attempt to patch over this hole -- by showing that the shard is a piece from a mirror found in Aberforth's house, but otherwise giving it the book backstory of him having bought it from Mundungus Fletcher -- but this only accomplishes making the whole thing into a bit of a VoodooShark, as it begs the question of why Aberforth would by a broken mirror, and it still doesn't explain why Harry ended up with a shard from it in his sock.

* The Two-Way Mirror that Sirus gives to Harry in ''The Order of the Phoenix'' is left out of the film. This creates some rather glaring problems further down the lines for the ''Deathly Hallows'' film. In the book, Harry ended up smashing the mirror in frustration after a last ditch attempt to use it to [[spoiler:contact Sirus beyond the grave]]. After this, Harry decides to save a shard as a keepsake. Meanwhile, due to [[spoiler:Sirus' death]], the other mirror ends up in the hands of Mundungus Fletcher, who ends up selling it Dumbledore's brother, Aberforth. This leads to Harry observing a bright blue eye sometimes looking back at him from the shard, and due to the striking resemblance to Dumbledore's own eye, Harry ends up assuming that it is Dumbledore trying to [[spoiler:contact him from the afterlife]]. This why Harry, when imprisoned in the cellar of Bellatrix Lestrange's manor, looks at the shard and begs for help. His plea for help is heard by Aberforth, who in response sends Dobby to get break them out. In the film, however, absolutely none of this context is given at any point, so to someone only familiar with the films, it comes across as Harry just suddenly and randomly taking a strange mirror shard out of his sock and begging it for help, resulting in it somehow summoning Dobby.

* The Two-Way Mirror that Sirus gives to Harry in ''The Order of the Phoenix'' is left out of the film. This creates some rather glaring problems further down the lines for the ''Deathly Hallows'' film. In the book, Harry ended up smashing the mirror in frustration after a last ditch attempt to use it to [[spoiler:contact Sirus beyond the grave]]. After this, Harry decides to save a shard as a keepsake. Meanwhile, due to [[spoiler:Sirus' death]], the other mirror ends up in the hands of Mundungus Fletcher, who ends up selling it Dumbledore's brother, Aberforth. This leads to Harry observing a bright blue eye sometimes looking back at him from the shard, and due to the striking resemblance to Dumbledore's own eye, Harry ends up assuming that it is Dumbledore trying to [[spoiler:contact him from the afterlife]]. This why Harry, when imprisoned in the cellar of Bellatrix Lestrange's manor, looks at the shard and begs for help. His plea for help is heard by Aberforth, who in response sends Dobby to get break them out. In the film, however, absolutely none of this context is given at any point, so to someone only familiar with the films, it comes across as Harry just suddenly and randomly taking a strange mirror shard out of his sock and begging it for help, resulting it somehow summoning Dobby.

* The Two-Way Mirror that Sirus gives to Harry in ''The Order of the Phoenix'' is left out of the film. This creates some rather glaring problems further down the lines for the ''Deathly Hallows'' film. In the book, Harry ended up smashing the mirror in frustration after a last ditch attempt to use it to [[spoiler:contact Sirus beyond the grave]]. After this, Harry decides to save a shard as a keepsake. Meanwhile, due to [[spoiler:Sirus' death]], the other mirror ends up in the hands of Mundungus Fletcher, who ends up selling it Dumbledore's brother, Aberforth. This leads to Harry observing a bright blue eye sometimes looking back at him from the shard, and due to the striking resemblance to Dumbledore's own eye, Harry ends up assuming that it is Dumbledore trying to [[spoiler:contact him from the afterlife]]. This why Harry, when imprisoned in the cellar of Bellatrix Lestrange's manor, looks at the shard and begs for help. His plea for help is heard by Aberforth, who in response sends Dobby to get break them out. In the film, however, absolutely none of this context is given at any point, so to someone only familiar with the films, it comes across as Harry just randomly taking a strange mirror shard out of his sock and begging it for help, resulting it somehow summoning Dobby for some reason.

* The Two-Way Mirror that Sirus gives to Harry in ''The Order of the Phoenix'' is left out of the film. This creates some rather glaring problems further down the lines for the ''Deadly Hallows'' film. In the book, Harry ended up smashing the mirror in frustration after a last ditch attempt to use it to [[spoiler:contact Sirus beyond the grave]]. After this, Harry decides to save a shard as a keepsake. Meanwhile, due to [[spoiler:Sirus' death]], the other mirror ends up in the hands of Mundungus Fletcher, who ends up selling it Dumbledore's brother, Aberforth. This leads to Harry observing a bright blue eye sometimes looking back at him from the shard, and due to the striking resemblance to Dumbledore's own eye, Harry ends up assuming that it is Dumbledore trying to [[spoiler:contact him from the afterlife]]. This why Harry, when imprisoned in the cellar of Bellatrix Lestrange's manor, looks at the shard and begs for help. His plea for help is heard by Aberforth, who in response sends Dobby to get break them out. In the film, however, absolutely none of this context is given at any point, so to someone only familiar with the films, it comes across as Harry just randomly taking a strange mirror shard out of his sock and begging it for help, resulting it somehow summoning Dobby for some reason.

* The final movie removes Dumbledore's explanation of why [[spoiler:Voldemort's Killing Curse in the forest failed to work on Harry]], leaving [[spoiler:his survival (and why it ''had'' to be Voldemort himself who cast the curse)]] a mystery with no "movie-canon" explanation. While it does explicitly explain why the [[spoiler:Elder Wand wouldn't work properly for Voldemort]] in the film (and [[spoiler:the failure of the Killing Curse]] could be explained simply by that), and Dumbledore also mentions that [[spoiler:Voldemort's SoulFragment]] is now gone (implying it might have served as PlotArmor), a question mark is still left behind on the completeness of the answer compared with the book's. (Then again, YMMV on whether or not adding [[spoiler: "And Voldemort's got your blood in him which means you're still protecting by your mother's sacrifice"]] really adds anything to the explanation: J.K. Rowling herself stated that [[spoiler: Harry's survival]] has as much to do with personal choice as the mechanics involved.)

* The third movie never mentions who Messrs. Moony, Wormtail, Padfoot, and Prongs are. This caused confusion among some audience members during the fifth movie when Harry wrote a letter to "Padfoot" without mentioning his given name. Plus Pettigrew being referred to exclusively as "Wormtail" in the fourth film. And it's now a mystery how Lupin knows how the map works.