History SeriesContinuityError / LiveActionTV

** The planet New Earth is given two contradictory and mutually exclusive locations. In [[Recap/DoctorWhoS28E1NewEarth "New Earth"]], the Doctor claims it's in the galaxy [[https://en.wikipedia.org/wiki/Messier_87 M87]]. In [[Recap//DoctorWhoS29E3{{Gridlock}} "Gridlock"]], he says it's 50,000 light-years from where Old Earth [[EarthShatteringKaboom used]] to be. M87, for those who didn't click on the link, is ''twenty million'' light-years from Earth, even accounting for the fact that both episodes take place five billion years in the future.

** The planet New Earth is given two contradictory and mutually exclusive locations. In [[Recap/DoctorWhoS28E1NewEarth "New Earth"]], the Doctor claims it's in the galaxy [[https://en.wikipedia.org/wiki/Messier_87 M87]]. In [[Recap//DoctorWhoS29E3Gridlock "Gridlock"]], he says it's 50,000 light-years from where Old Earth [[EarthShatteringKaboom used]] to be. M87, for those who didn't click on the link, is ''twenty million'' light-years from Earth, even accounting for the fact that both episodes take place five billion years in the future.

** The show has two different origins for the Loch Ness monster: an alien cyborg ([[Recap/DoctorWhoS13E1TerrorOfTheZygons "Terror of the Zygons"]]) and a mutated overlord thrown back in time (Recap/DoctorWhoS22E5Timelash "Timelash"]]). Similarly, there has been at least three and up to five monsters who are {{Satan}} - Azal ([[Recap/DoctorWhoS8E5TheDaemons "The Dæmons"]]), Sutekh ([[Recap/DoctorWhoS13E3PyramidsOfMars "Pyramids of Mars"]]), the Beast ([[Recap/DoctorWhoS28E9TheSatanPit "The Satan Pit"]]), arguably the Black Guardian (the Key to Time {{Arc}}) and Scratchman, depending on whether you want to consider an [[DevelopmentHell unmade]] film part of the Whoniverse or not.

** The show has two different origins for the Loch Ness monster: an alien cyborg ("Terror of the Zygons") and a mutated overlord thrown back in time ("Timelash"). Similarly, there has been at least three and up to five monsters who are {{Satan}} - Azal ("The Daemons"), Sutekh ("Pyramids of Mars"), the Beast ("The Satan Pit"), arguably the Black Guardian (the Key to Time {{Arc}}) and Scratchman depending on whether you want to consider an [[DevelopmentHell unmade]] film part of the Whoniverse or not.
** Also from ''Who'' is the notorious UNIT dating problem. In [[Recap/DoctorWhoS13E3PyramidsOfMars "Pyramids of Mars"]], Sarah Jane Smith is from 1980, and the last time she was there, the Brigadier was still heading UNIT ([[Recap/DoctorWhoS13E1TerrorOfTheZygons "Terror of the Zygons"]]). In [[Recap/DoctorWhoS20E3MawdrynUndead "Mawdryn Undead"]], the Brigadier retired in 1976, taking up a position as mathematics teacher through 1983. Lampshaded in the series 4 episode [[Recap/DoctorWhoS30E4TheSontaranStratagem "The Sontaran Stratagem"]], when the Doctor tells Donna he used to work for Unit in the '70s... or maybe the '80s...

** In the revived ''Doctor Who'', the Doctor continually insists that he is 900 years old, which by [[Recap/DoctorWhoS32E1TheImpossibleAstronaut "The Impossible Astronaut"]] became 909. This despite the fact that in the original series, the sixth Doctor also claimed to be 900 years old, and the seventh said once that he was 953 in [[Recap/DoctorWhoS24E1TimeAndTheRani "Time and the Rani"]]. Given that the remainder of the seventh Doctor's life and all of the eighth Doctor's life is lived out after this point, the ninth and tenth Doctors must be far older than 900 years old. And to top it all off, he's used the nine hundred figure for his age, how many years he's been time traveling, how much "phone box" travel he's done (which would have to be from the first episode of the original series, when it got stuck like that, and not how long he's used the TARDIS) ''and'' how long he's been using "the Doctor" as a nom de plume, four discrete and mutually exclusive things. He may just like the number. WordOfGod states that he has no way of remembering his exact age, and even if he did, he might be in denial over the big 1-0-0-0. By "Closing Time", he finally pushes past the 1100 mark, however, it's clear from dialogue in "The Impossible Astronaut" that hundreds of years have passed since the previous episode "The God Complex". Subjected to an InternalRetcon in [[Recap/DoctorWho50thASTheDayOfTheDoctor The Day of the Doctor]], where the Doctor admits he doesn't actually know how old he is. He knows he's about 400 years older than his previous incarnation, but that's about it.
*** Likewise, Romana loses 15 years between [[Recap/DoctorWhoS16E1TheRibosOperation The Ribos Operation]] (140) and [[Recap/DoctorWhoS17E2CityOfDeath City of Death]] (125).

** In general, the show has even come up with an in-universe explanation which can act as a general retcon whenever needed; the Time War has just gone around screwing with the time line! Whole events have literally been wiped out of existence (unless you're a time-traveler, because then you can remember them).
** In the earliest episodes, they talked about the ship. TARDIS was only Susan's nickname for it. However, since other Time Lords [[spoiler:and the TARDIS itself in "The Doctor's Wife"]] refer to the machine in question as such, this more likely either a very early {{Retcon}} or EarlyInstallmentWeirdness. Although, confusingly, it is also referred to as a "TT Capsule" (presumable Time Travel) by a great many Time Lords as well, in the stories that take place on Gallifrey during the 4th Doctor's time.

** There are many, ''many'' examples of characters getting obvious (although not drastic) haircuts and similar appearance alterations between supposedly consecutive episodes. The Chief Scientist in "The War Games" suddenly grows a beard over a few hours plot time; the Doctor in "The Ark in Space" gets his long hair [[FunnyAfro layered]] while brooding in a cryogenic chamber anticipating an attack from the Wirrn; Barbara in one story gets captured, spends an episode imprisoned, and escapes with a new tan; Harry's sideburns get noticeably trimmed while in mid-teleport...
** In "Pyramids of Mars", the plot hinges on the idea that the TARDIS' controls are 'isomorphic' and can only be manipulated by the Doctor, despite characters like Susan, Jo and Harry having piloted it in previous stories. Creator/RobertHolmes later offered the explanation that it was because the Doctor was lying, though Sutekh's ability to read the Doctor's mind [[FanDislikedExplanation makes this unpopular]]. The same story also has the Doctor make a throwaway reference to having been blamed for causing the Great Fire of London in 1666... something that a Fifth Doctor plot later revolves around. Lying again?
** Dating inconsistencies (see UNIT dating, above) have reemerged in the modern era of the series in several places. Two of particular note: the 2007 episode "Utopia" establishes that the universe survives for at least 100 ''trillion'' years. This is stated directly in dialogue and is one of the major plot points upon which the 2007 season finale was pinned. Fast-forward to the 2015 episode "Hell Bent" in which the Doctor travels to the end of the universe which is now said to be only a ''few billion'' years into the future. Even taking into account the fact that, in the British numbering system, a "billion" is the equivalent to a North American "trillion", it still doesn't work. Another inconsistency involves the companion Clara Oswald, who is said to be 24 when she joins the Doctor in early 2013, but 27 come episodes aired in 2014; a possible workaround occurs in the 2014 episode "In the Forest of the Night" when the Doctor implies that the episode takes place in 2016, which would fix the issue. Clara is [[spoiler: KilledOffForReal]] in the 2015 episode "Face the Raven" which, based upon the 2016 date which was followed by a Christmas special could not occur earlier than 2017. However, the spin-off series ''Series/Class2016'' is explicitly set in 2016, with dates given on screen, and Clara's [[spoiler: death]] is not only directly referenced, it is indicated (based on comparison to dates given in the series) to have taken place in 2015.

* One of the most famous cases is ''Series/TheGoldenGirls''. At some point, they hired a new writing team who simply ignored previous continuity in favor of RuleOfFunny. Some famous examples:
** In one episode, Dorothy mentions that Rose is allergic to cats. However, in a flashback of how Rose and Blanche first meet, Rose mentions that she was thrown out of her apartment because her landlord didn't allow her to keep a cat she found, and was holding at the time. Although, this could be {{Handwaved}} with Rose's caring nature, she might put her personal pain aside to help an animal in need. Or that Rose developed the allergy after that incident.
** The most famous is Dorothy's children. Dorothy and Stan were married for 38 years, and the show began two years after that. Considering Dorothy had a shotgun wedding, one of her children needs to be at 40 for this to make sense. Although both of her kids were played by multiple actors over the years, neither of them appear to be over 30.
*** Indeed, in his first appearance in season 2, Michael Zbornak is explicitly stated as being 29 years old, while in the season 3 episode where he reveals he's marrying an older woman, he's explicitly stated as being 23 (Lorraine is 44). In his last appearance in season 5, his age is again explicitly given - this time as 30. (Scott Jacoby, the actor who portrayed Michael was born in 1956, making him 30 in his first episode, and 33 in his last appearance.)
** Dorothy is also stated to be a grandmother early on in the series, having a grandson named Robby. However, neither of Dorothy's children that make an appearance are shown to have children.
** DependingOnTheWriter, Blanche can have between 4 and 6 children. [They eventually tried to knock these together, however; in one instance, she had previously specified she was talking about her four sons (she was offering to give Dorothy one of her sons in exchange for keeping a Mercedes they couldn't afford, saying "I have had four kids, I have never had a Mercedes.") All of her kids were named however: Biff, Doug, Skippy, Matthew, Janet, and Rebecca.]
** Rose was adopted as a baby in one ep and at age 8 in another. [Again, they tried to weld these together by saying she was abandoned on the doorstep of the orphanage as a baby and was actually adopted at 8.]
* ''Series/WizardsOfWaverlyPlace''
** In the episode "Art Teacher", Mr. Laritate is surprised that his phone gets text messages when a teacher "texted in her resignation." In a later episode, he apparently still doesn't know what a text message is.
** In the episode "Monster Hunter", Jerry says that he remembers when Justin was still turning bricks into rabbits and Justin nostalgically responds "Edgebono Utoosis". However, in "The Crazy 10 Minute Sale", it's shown that "Edgebono Utoosis" is a spell to create a duplicate of whatever it's cast on. Not to mention Justin never turned a brick into anything. He duplicated a rabbit, and in a totally different episode, Alex turned a dove into a brick.
** Another episode had Alex say that every wizard learns the zombie language when they're little, but an earlier episode established she didn't know she was a wizard when she was little.
** In "Make it Happen", Jerry says his father was a rodeo clown, but in "Rock Around the Clock", Grandpa Russo clearly owns the sandwich shop.
* ''Franchise/StarTrek'' has a ridiculous number of examples.
** In the TNG episode "Relics", Scotty is released from a transporter buffer where he was trapped for hundreds of years and initially believes that Geordi and Riker were sent by Kirk. However, ''Film/StarTrekGenerations'' reveals that Scotty was present when Kirk was sucked into the Nexus from ''Enterprise-B'' (this was due to Scotty being placed in the movie at the last minute since Leonard Nimoy wasn't available).
** In their first appearance, the Ferengi were aggressive, militaristic imperialists. In later appearances, they are portrayed as craven, greedy people with few cultural arts outside peddling and trading. This was an AuthorsSavingThrow; they'd planned to make the Ferengi the new [[BigBad Big Bad Aliens]] of the franchise, and they didn't realize until the episode was already wrapped and aired that they'd utterly failed at it. So they cut their losses, rewrote the Ferengi (and changed their uniforms to something less silly), and brought back the [[MagnificentBastard Romulans]]. (The ExpandedUniverse has a cute explanation for this: the HumanPopsicle stock broker from the 20th century who also appeared in the episode where Romulans first reappeared was eventually made the Federation ambassador to the Ferengei homeworld. This lead to the revelation that the hostilities were due to the two species not being able to understand each other, and the unfrozen stock broker was able to bridge the divide.)
** The original series episode "Space Seed" was made during a time when a specific year wasn't yet assigned to the canon, so it references things in blocks of time... but misses the mark by a hundred years when ''Wrath of Khan'' came out. Whoops.
** The Borg story has a sketchy chronology. Q set Picard's ''Enterprise'' thousands of light-years to find the Borg for the first time, and eighteen months later they came looking for Earth. Guinan identified the Borg in their introductory episode and it was later revealed that Guinan and her people migrated during Kirk's time. ''Voyager'' introduces Federation scientists (Seven of Nine's parents) studying the Borg long before Picard's first contact. It messed up what was inferred in the original episode, but it does make some sense that Guinan's people could have reported it to the Federation and it just didn't become common knowledge until the official first contact.
** In the Borg's first appearance in "Q Who?" they're only interested in "consuming" technology, and ignore other lifeforms unless they see them as a threat. When they take Picard in "Best of Both Worlds", he's chosen to be a spokesman, not a drone. It's only after this that we're told assimilating other lifeforms is their standard MO, and ''always was''.
** The vanished outposts in the first season finale, "The Neutral Zone", were meant to be foreshadowing of the Borg (in "Q Who?", they encounter an identical pattern of destruction after Q displaces them), implying that the Borg were probing the edge of Federation space even before Q made formal introductions. This is never mentioned again, and Guinan would later claim that, thanks to Q's intervention, the Borg discovered humanity centuries sooner than they ought to have done.
** Data's cat was repeatedly referred to as male since it was introduced, then suddenly became female in the last season and even had kittens. Some FanWank this as his owning several cats over the years and giving them all the same name, which would seem to be in character. Not to mention the fact that Spot was a different breed in his/her first appearance.
** There were continual goofs in whether Lieutenant Commanders are referred to as "Lieutenant" or "Commander" formally. They could probably have gotten away with either regardless of real-world behaviors if they had just chosen one and stuck with it.
** In the ''Series/StarTrekDeepSpaceNine'' episode "The Alternate", Sisko strongly implies that his father is dead. This contradicts later episodes where his father is very much alive and running a restaurant in New Orleans.
** As pointed out by Phil Farrand in the ''Nitpicker's Guides'', O'Brien is casually treated as an officer (and once referred to as a lieutenant) in ''Next Gen'' but is explicity and insistently a noncommissioned officer in ''Deep Space Nine''.
** Also in ''Series/StarTrekDeepSpaceNine''; in one of Ezri Dax's early episodes where she's having trouble dealing with the responsibilities of being Dax's host, Sisko taunts her by suggesting she can return to Trill and become one of the caretakers of the immature symbioties. He then goes on to describe that her duties would entail stirring the mud in the vats which contain the immature symbioties. The trouble is that we've already seen the subterranean caverns he's talking about, and the immature symbioties swim around in immense subterranean rivers, not mud.

* ''Series/DoctorWho'':
** The show has two different origins for the Loch Ness monster: an alien cyborg ("Terror of the Zygons") and a mutated overlord thrown back in time ("Timelash"). Similarly, there has been at least three and up to five monsters who are {{Satan}} - Azal ("The Daemons"), Sutekh ("Pyramids of Mars"), the Beast ("The Satan Pit"), arguably the Black Guardian (the Key to Time {{Arc}}) and Scratchman depending on whether you want to consider an [[DevelopmentHell unmade]] film part of the Whoniverse or not.
** Also from ''Who'' is the notorious UNIT dating problem. In [[Recap/DoctorWhoS13E3PyramidsOfMars "Pyramids of Mars"]], Sarah Jane Smith is from 1980, and the last time she was there, the Brigadier was still heading UNIT ([[Recap/DoctorWhoS13E1TerrorOfTheZygons "Terror of the Zygons"]]). In [[Recap/DoctorWhoS20E3MawdrynUndead "Mawdryn Undead"]], the Brigadier retired in 1976, taking up a position as mathematics teacher through 1983. Lampshaded in the series 4 episode [[Recap/DoctorWhoS30E4TheSontaranStratagem "The Sontaran Stratagem"]], when the Doctor tells Donna he used to work for Unit in the '70s... or maybe the '80s...
** This is compounded by the fact that in a deleted scene from Sarah Jane's first serial, [[Recap/DoctorWhoS11E1TheTimeWarrior "The Time Warrior"]], she was scripted to explicitly tell Lynx she had come from the year 1974. This apparently stemmed from a dispute between the writers of the show as to whether the UNIT years should happen in the present day or slightly in the future (another such continuity snarl line happened in [[Recap/DoctorWhoS10E5TheGreenDeath "The Green Death"]], where one of the Global Chemicals employees tells The Brigadier that they'd recently swapped out their cutting gear for a "thermal lance.").
** In the revived ''Doctor Who'', the Doctor continually insists that he is 900 years old, which by [[Recap/DoctorWhoS32E1TheImpossibleAstronaut "The Impossible Astronaut"]] became 909. This despite the fact that in the original series, the sixth Doctor also claimed to be 900 years old, and the seventh said once that he was 953 in [[Recap/DoctorWhoS24E1TimeAndTheRani "Time and the Rani"]]. Given that the remainder of the seventh Doctor's life and all of the eighth Doctor's life is lived out after this point, the ninth and tenth Doctors must be far older than 900 years old. And to top it all off, he's used the nine hundred figure for his age, how many years he's been time traveling, how much "phone box" travel he's done (which would have to be from the first episode of the original series, when it got stuck like that, and not how long he's used the TARDIS) ''and'' how long he's been using "the Doctor" as a nom de plume, four discrete and mutually exclusive things. He may just like the number. WordOfGod states that he has no way of remembering his exact age, and even if he did, he might be in denial over the big 1-0-0-0. By "Closing Time", he finally pushes past the 1100 mark, however, it's clear from dialogue in "The Impossible Astronaut" that hundreds of years have passed since the previous episode "The God Complex". Subjected to an InternalRetcon in [[Recap/DoctorWho50thASTheDayOfTheDoctor The Day of the Doctor]], where the Doctor admits he doesn't actually know how old he is. He knows he's about 400 years older than his previous incarnation, but that's about it.
*** Likewise, Romana loses 15 years between [[Recap/DoctorWhoS16E1TheRibosOperation The Ribos Operation]] (140) and [[Recap/DoctorWhoS17E2CityOfDeath City of Death]] (125).
** In [[Recap/DoctorWhoS3E10TheWarMachines "The War Machines"]] the computer WOTAN actually says "Doctor Who is required". Even the most casual fans know that [[IAmNotShazam he isn't called that]]. The name is only ever used as a joke, e.g. "Doctor? Doctor who?"
** In general, the show has even come up with an in-universe explanation which can act as a general retcon whenever needed; the Time War has just gone around screwing with the time line! Whole events have literally been wiped out of existence (unless you're a time-traveler, because then you can remember them).
** In the earliest episodes, they talked about the ship. TARDIS was only Susan's nickname for it. However, since other Time Lords [[spoiler:and the TARDIS itself in "The Doctor's Wife"]] refer to the machine in question as such, this more likely either a very early {{Retcon}} or EarlyInstallmentWeirdness. Although, confusingly, it is also referred to as a "TT Capsule" (presumable Time Travel) by a great many Time Lords as well, in the stories that take place on Gallifrey during the 4th Doctor's time.
*** This is given a fix by ''AudioPlay/BigFinishDoctorWho'' in the audio drama ''The Beginning''; the First Doctor calls it "the Ship", as he does in the series, but when Susan first mentions "TARDIS" he replies "Oh, you've heard that name". She thinks he's being silly and continues to think of it as her own name for the Ship, but the implication is that she wasn't the first to coin the acronym.
** The original series had been on for over a decade before they ever addressed the issue of the Doctor and his companions being able to understand the natives no matter what era they were in or planet they were on. When a companion actually made mention of it after having been travelling with him for several years, it was a big deal and a clue that someone was controlling her mind. In the new series, it's been brought up several times with the Doctor being unconcerned that they've noticed.
** In the ''Fourth Doctor Adventures'' story "Destination: Nerva", the Fourth Doctor rambles about a "Butler named Butler", a character from an audio drama recorded before "Destination: Nerva" but coming after it in the Doctor's timeline. The line was a Creator/TomBaker adlib, and he didn't really care about such things. FanWank [[WordOfGod Of God]] is that the NegativeSpaceWedgie was allowing the Doctor to precognate future events.
** There are many, ''many'' examples of characters getting obvious (although not drastic) haircuts and similar appearance alterations between supposedly consecutive episodes. The Chief Scientist in "The War Games" suddenly grows a beard over a few hours plot time; the Doctor in "The Ark in Space" gets his long hair [[FunnyAfro layered]] while brooding in a cryogenic chamber anticipating an attack from the Wirrn; Barbara in one story gets captured, spends an episode imprisoned, and escapes with a new tan; Harry's sideburns get noticeably trimmed while in mid-teleport...
** In "Pyramids of Mars", the plot hinges on the idea that the TARDIS' controls are 'isomorphic' and can only be manipulated by the Doctor, despite characters like Susan, Jo and Harry having piloted it in previous stories. Creator/RobertHolmes later offered the explanation that it was because the Doctor was lying, though Sutekh's ability to read the Doctor's mind [[FanDislikedExplanation makes this unpopular]]. The same story also has the Doctor make a throwaway reference to having been blamed for causing the Great Fire of London in 1666... something that a Fifth Doctor plot later revolves around. Lying again?
* ''Series/ICarly''
** In an early episode, Carly never takes baths because she hates sitting ''in her own wet dirt''. Come ''iToe Fatcakes'', her entire B-plot revolves around her having a bath and somehow getting stuck in it.
** Another episode has Sam endure a Carly makeover to become "girlier" to impress a boy she likes. A few seasons later, Sam is revealed to have been a pageant girl for a long time, and there's no way she would've needed Carly's help to change to be a little girlier.

* ''Series/SoWeird'': In season 2, Fiona has a pet cat, and has had it for some time. A long-haired cat at that. In season 3, her mother is severely allergic to cats and can't stand to be near one. (Though it ''is'' possible to ''develop'' a cat allergy...)
* ''Series/{{Soap}}'': In the very first episode, Chester claims to be diabetic when Benson brings him coffee with sugar. A season or so later, trying to justify his sex addiction, he tells his wife, "If I had diabetes, you couldn't blame me for not being able to have sugar."
* ''Series/IDreamOfJeannie''
** It's established early on that genies can't be photographed. And then along comes a plot when there's a small scandal because Jeannie's been mistaken for someone else, and a paparazzi shot of her and Tony gets into the local paper. And then they go back in the wedding episode, where they have to have a plastic stand-in dummy switch with Jeannie whenever a camera is focused on them, and they end up having to steal the video that was made of the wedding. Make up your minds!
** And speaking of their marriage, it's spelled out in a relatively early that Jeannie would lose her powers should she marry Tony, which almost causes him to marry her on the spot, until he learns that any children they have might have genie powers. Then they get married in the final season. Surprise surprise, she doesn't lose her powers.
** And she seemed to personally know a lot of historical figures that were around in the 2000 years that she was supposed to be trapped in her bottle...
** The most infamous: originally, Jeannie was a human girl, until the Blue Djinn turned her into a genie and trapped her in a bottle after she refused to marry him. Later episodes not only flat out state that she was born a genie, but her other genie relatives often come to visit.
* ''Series/TheAdventuresOfSuperman'' has one episode in which Jimmy gives his middle name as Bartholomew, and another where a nameplate says "James J. Olsen"
* ''Series/FullHouse''
** In the first episode, Danny tells his mother to return to his father in such a way that implies that his parents are married. Later episodes tell us that Danny's parents have been divorced since childhood.
** Steve's last name seems to have changed from Peters (when first introduced) to Hale (in the prom episode). Of course, before that, there was Jesse -- who had the last name "Cochran" in Season 1, but "Katsopolis" for the rest of the series. WordOfGod states that change was [[RetCon deliberate]], as John Stamos requested his Greek heritage be reflected in the series.
** An early episode shows Jesse attending his high school reunion (with a flashback taking place shortly before graduation). Several seasons later has him say he dropped out of high school (right in the middle of a class, no less) and had been keeping it a secret from everyone else. Even if this did fit continuity, it's questionable how Danny, his long-time brother-in-law, could not have known this.
** In early episodes, Jesse was athletic and obsessed with sports. In later episodes, Jesse was a bit out of shape and [[GretzkyHasTheBall knew absolutely nothing about sports]].
** In one episode Joey claims he has never had the chicken pox, however in a later episode his father mentions that he did have it as a little boy.
** In the pilot, DJ mentions that Kimmy Gibbler has three sisters. Later on, Kimmy mentions an older brother named Garth, who never appeared. In ''Series/FullerHouse'', we meet her [[RememberTheNewGuy never-before-mentioned]] younger brother, Jimmy.
* ''Series/ILoveLucy'' gives Ethel several different middle names, and Ricky two different ''first'' names.
* American version of ''Series/{{The Office|US}}'':
** Pam [[spoiler:Halpert nee]] Beesly has had her [[spoiler:maiden]] name in various incarnations; Pam Beasley, Pam Beesley, Pamela Jean Beesly, the now-canon Pamela ''Morgan'' Beesly...
** Meredith went from having two kids to having one, and from being an accountant to a supplier relations rep.
** On an episode of the Michael wants to throw a birthday party and asks Pam when the next birthday in the office is. She tells him the next birthday is Meredith's, which is "next month." In another episode, Jim says that it's "birthday month" and that "Kelly's was last week, Creed's is today, Oscar's is next week, and Meredith's is at the end of the month."
** In one episode, Jim says that he's had a crush on Pam since her first day at Dunder-Mifflin. In another, he says he's had a crush on her since she showed him to his desk on his first day. Obviously, that only makes sense if they both started on the same day, but it seems odd that he wouldn't refer to it as "our first day" if that were the case.
** {{Word of God}} -- specifically, Greg Daniels -- says that this is the writers being forgetful. He also says that he personally prefers the story Jim tells of his "worst first date", or the first day Pam started.

* The first ''Series/GrowingPains'' ReunionShow mentions that the Seavers bought a new house a few blocks from the old one, and has Carol marrying a man with a son. In the second one, Carol and her now differently-surnamed husband are expecting their first child, and the plot revolves around what is supposedly the house from the series, though given the conversion from a stagey sitcom to a realistic TV-movie, you'd be hard pressed to recognize it.
* ''Series/MyNameIsEarl'' has a few of these mostly because of the high number of {{flashback}}s they do, often covering very close events in the timeline.
** The most general ones are that the Hickey brothers didn't know Joy until Earl married her and Catalina until after Earl's karmic revelation. All the flashbacks make you wonder a little why they didn't know Joy most of their lives and Catalina during the six years she had immigrated to America, as both seemed to be regulars at the Crab Shack.
** A big one is that they established that Earl married Joy in November (six months pregnant with her son Dodge) and they had a [[MillenniumBug [=Y2K=]]] adventure for their first New Years together. The last episode showed that Dodge was conceived on Halloween...
* ''Series/TheCosbyShow''
** In the first episode, Claire asks Cliff "Why do we have four children?" and he answers "Because we didn't want five." Only a few episodes later, viewers are introduced to college student Sondra, the oldest of their ''five'' children. According to WordOfGod, it was felt to be appropriate that the couple be shown with a college-age child and demonstrate to viewers what was expected of the other children.
** Also, in an early episode Cliff's office door shows his name as Clifford. Subsequent episodes established his name as Heathcliff.
* Okay, we all know ''Series/MorkAndMindy'' was pretty much just a fun show about an AmusingAlien who learns something about Earth every week, and even more so it was [[TheCastShowoff an excuse to have]] Creator/RobinWilliams [[HarpoDoesSomethingFunny show off his improv]]. But there are just some things that cannot be excused by RuleOfFunny. Such as the season four episode "Three the Hard Way" when Mork [[MisterSeahorse "lays" an egg out of his stomach]], he reminds Mindy that he is a test tube child without a navel, and then displays the navel that was formed when the egg came out. But in the ''first season'' episode "A Mommy for Morky", Mork, mentally aged to a toddler lifts up his shirt and says "I know where my bellybutton is!". And it's there. He was already established as a test tube child, but it's there. And Mindy damn well saw it. And the writers damn well ignored it apparently.
* ''Theatre/TheOddCouple'' did multiple episodes showing how Felix and Oscar "first met." Also, one episode establishes that one of them didn't have any wedding photos; in another episode, he is seen looking at his wedding photos.
* The BBC's ''Series/RobinHood'':
** Robin of Locksley and Guy of Gisborne meet for what is clearly the first time in the pilot episode. In season three the writers try to pull off a massive RetCon with a WholeEpisodeFlashback that demonstrates that the two were young boys together. They ''might'' have gotten away with it if the flashback hadn't also included some fairly dramatic revelations: Guy's mother and Robin's father were engaged, that Robin lets Guy take the blame for a prank that nearly gets him executed, and that their parents end up dying together in a fire. The fact that neither Robin or Guy has ''ever'' mentioned any of this before is more than a little absurd.
** A minor issue is the fact that Guy wrongly believes that he was responsible for the fire that killed his parents, even saying that it's haunted him throughout his lifetime. However, he didn't seem particularly "haunted" when he set fire to Marian's house back in season two.
** He also claims back in season one that he's never been to a wedding before. This seems rather strange when the Flashback shows that he had a perfectly normal childhood in Locksley (though admittedly, not impossible).
* ''Series/{{Charmed}}''
** In the hundredth episode, Paige sees her own grave in an alternate universe, which states her birth as being in 1975. However, in the episode after she was introduced, she states that she last saw the nun she was taken to as a baby on August 2nd, 1977, and it's heavily implied that this was the same night her parents took her to the church to be adopted, the night she was born. Even if this implication were to be discarded, Paige's older sister Phoebe is established to have been born in very late 1975, and it's also established that Phoebe was a toddler when Paige was conceived, so they weren't twins. As such, the only explanation which makes sense is that the writers forgot the year Paige was supposed to be born in (or, of course, that in an alternate universe Paige was born nearly two years earlier and no-one mentioned it).
** Also, in a season 1 episode, we learn that the girls' mother died shortly after Phoebe was born, MUCH too shortly after to have conceived and borne another child post-Phoebe.
** And yet, in a Season 2 episode, much earlier than when Paige became necessary as a character to replace Prue, their mother's date of death is established as February 28, 1978.
** The girls' Father was named Victor Halliwell in season 1, but later his name was Bennet and Halliwell was a name that had been passed from mother to daughter in defiance of social convention for an unspecified period of time.
** Also for Paige, she was there when the sisters first vanquished The Source of All Evil, and still there when they did it a few more times. But in the final season, when he was being called back, Paige asks how they vanquished the Source last time. Specifically she says "how did ''you'' do it?", which is very odd.
** Penny the sisters' grandmother was first mentioned to have married six times. This was later changed to that she had only been married four times but engaged six times.
* ''Series/ATouchOfCloth'', perhaps uniquely, ''deliberately creates a continuity error'' purely for RuleOfFunny. Early in the first episode of Series 2, Tom Boss off-handedly mentions that a pound of heroin has gone missing from the vice squad tuck shop. Later in the episode, once Jack Cloth has gotten involved in the case and gone undercover to infiltrate Macratty's gang, what does he use to gain Macratty's trust? [[ChekhovsGun A pound of heroin from the vice squad tuck shop]]...the same one that was stolen ''before he was even involved in the case''. This being a parody with NoFourthWall, [[LampshadeHanging the resulting continuity error is soon pointed out to Jack by another officer]]...and as Jack rants that he doesn't need to obey the laws of continuity, ''[[CrowningMomentOfFunny his beard briefly vanishes]]'' [[CrowningMomentOfFunny only to reappear when the camera angle changes]].

* ''Series/{{Monk}}''
** In one episode, Lieutenant Disher mentions that he doesn't have any uncles. A few seasons later, an episode revolves around him inheriting his uncle's farm.
** In season 3, we meet Joe Christi, a former cop who tells Sharona that he was present when Monk got the call about his wife's death. The series finale depicts this scene, and there's no Joe to be found.

* In an episode of ''Series/TheSuiteLifeOfZackAndCody'', London is shown to be very competent in physical sports. In an episode of ''The Suite Life on Deck'', she needs Zack's help. Did she leave her muscles in Boston?
* ''Series/{{Frasier}}''
** In the episode with Martin's brother, a backstory about a longstanding family feud is written in to attempt to explain why this character's never even been mentioned before -- which might work, if Martin hadn't specifically mentioned in a previous episode that he "never had a brother". It's a stretch, but it could be explained that the feud was bad enough that Martin [[IHaveNoSon wouldn't even acknowledge his brother's existence]]. Except there really isn't a feud between Martin and his brother at all -- the brother's wife is mad at Frasier is about the entirety of it. The brothers are even looking forward to chatting, once she (temporarily) forgives Frasier.
** On a related note, the series avoided another continuity error with a fairly clever RetCon. In ''Frasier'', Martin is a retired cop, but in an episode of ''Series/{{Cheers}}'' Frasier described him as a scientist... and dead. When [[TheCameo Sam Mallone]] stops by and notes the discrepancy, Frasier says that he'd made that story up because he and Martin had been fighting at the time.
** There are some problems concerning the ages of Martin and Frasier. It is established that Martin was 21 years old and married to Hester when Frasier was born. There is another episode where Martin recalls being single at 22.
** In ''Cheers'', Frasier said he had no siblings. The first episode of ''Frasier'' he meets Niles at the coffee shop and they agree to start talking again. [[FridgeBrilliance Seems like it's just a Crane family tradition]] -- have a fight, pretend someone doesn't exist until reconciliation.
** Frasier's cat allergy seems to come and go.
* ''Aliens in America'' has an episode about Justin's fear of performing in public -- it's a plot point that he's a weak singer who freezes up so badly on stage that he wasn't allowed to sing in a school pageant that offered a role to anyone who showed up. A few episodes later, Justin's been a soloist in the school choir for years.
* ''Series/YoungBlades'': When Jacqueline meets [[Literature/TheThreeMusketeers The Great D'Artagnan]] in "Secrets of the Father," she excitedly goes on about how she used to swordfight with her brother while pretending to be The Great D'Artagnan. D'Artagnan (his son) clearly hears this and doesn't seem to be surprised or care. But several episodes later, in "Secrets," Jacqueline is suddenly very embarrassed about pretending to be The Great D'Artagnan and doesn't want D'Artagnan to know about it. When he overhears, he teases her about it. Neither of them seem to recall him finding out about it before.
* In season one of ''Series/BoyMeetsWorld'', Mr. Feeny informs his students that they will be the high school class of 2000. The characters actually graduate five seasons later, in 1998.
* ''Series/TheXFiles''
** In Season 1, Mulder describes the abduction of his sister, saying he couldn't see what was happening due to paralysis which prevented him from turning his head. In the season 2 premiere, the abduction is shown in a flashback, and young Fox is looking right at her as she floats out the window.
** Mulder claims to be red-green colorblind in an early episode, yet doesn't seem to have any trouble noticing what's odd about the green blood shed by an alien bounty hunter in a later season.
* ''Series/That70sShow''
** In the first episode, we learn that Eric and Donna have lived next door at least since age 4. In a later season, a flashback shows their first meeting, at age 8. Jackie is established in the first season as a sophomore, and the other characters as juniors in 1976. Five years later the characters (except Jackie) graduate at the same time. Three years after that, they all say goodbye to the 70's on New Years Eve, 1979. If not for the Halloween/Thanksgiving/Christmas episodes, you could say that each season represents less than one year of the characters' lives...
** In the second episode, we meet Donna's sister Tina, who is [[ChuckCunninghamSyndrome never seen or mentioned again]], save for one joke at the end of an episode that, while asking questions in the style of ''Series/{{Soap}}'', the narrator asks "What ever happened to Midge's other daughter Tina?"
* ''Series/WonderWoman'' TV Series: The pilot establishes that Paradise Island, at 1942, is a HiddenElfVillage of {{Action Girl}}s who had never seen a man in a thousand years. Princess Diana is elected TheChampion to travel to Men's world. She is the first Amazon to left Paradise Island in a thousand years. However, in third season episodes "Diana's Disappearing Act", [[ConMan Cagliostro]] claims that Wonder Woman has stopped all his lineage plans since the original Cagliostro (born in the 18th century) and in "Screaming Javelins", Diana remembers to have meet UsefulNotes/NapoleonBonaparte, implying not only that she was in Europe those years, but that she was already doing her superhero job.
* ''Series/SexAndTheCity'': Early in Season 6, Carrie is shopping with Samantha and tells her, "I don't buy furry shoes;" Carrie bought near-identical shoes (maxing out her credit card and allowing a friend to pay for them, no less) in ''Season 1''. It wouldn't have been so painful but for the perfect storm it landed in: beginning of popular internet fandoms, resurgence of popular {{Long Runners}}, beginning of DVD box sets in Season 1 - the fandom was livid.
* During Josh Safran's run as showrunner for ''Series/GossipGirl'', this became the norm, to the point where the writers didn't seem to remember what had happened just an episode or two prior.
** The whole mess with Chuck's parentage is one example, as is the fact that most of the time no one can seem to remember that Lily is his ''adpotive'' mother, not his stepmother. Safran himself used this trope gratuitously in order to prop the Dan/Blair pairing. For example the sudden references to Dan supposedly supporting Blair in season one by going to an essay contest she partook in. The actual episodes this would have taken place during had Dan disliking Blair to the point that he questions if he could be in a relationship with Serena because she could be friends with somebody like Blair. The numerous interviews Safran gave where he blatantly ignored the show's continuity to prop the pairing certainly did not sit well with the fans.
** Same thing happens to prop up the Dan/Serena pairing the season after the Dan/Blair pairing happens. Dan pretty much proclaims Blair as the love of his life, and the only one he wants. A season later and it's back to Serena and he says the exact same things to Serena that he told Blair.
** Not to mention the reveal that [[spoiler:Dan Humphrey]] is Gossip Girl requires the viewer to ignore or retcon large parts of the series in order for it to make even a little bit of sense.
* ''Series/{{CSI}}''
** Sara was stated to have a brother, then later said she was an only child
** Several items that were on the official CSI website character bios were changed in onscreen canon, like Catherine being from Bozeman, MT (likely given to 'CSI NY's Lindsay instead) and Grissom's father being involved in smuggling.
* ''Series/{{CSI NY}}''
** The writers forgot names several times. Don is Don Flack Jr. originally, but when his father was discussed, he wasn't referred to as Don Flack.
** Stella told a character in a season one ep that she lived at St. Basil's orphange until age 18, but later, a ep aired with a big plot point being that Stella lived with a foster sister who was molested and eventually killed her attacker. Unless she was just in and out of the orphanage.
** Mac tells the victim in the series pilot that he used to sit with his wife in the hospital, the indication being that she was found after 9/11 and died of her injuries. But later, the story was changed to no body ever being found. Some have [[{{Fanon}} fanwanked]] that perhaps she was ill before.
** Danny was originally from "a family of cops", later stuff contradicts that for the most part. The writers retconned that it was extened family, but not all fans buy it.
** Christine's late brother who was Mac's friend was Stan Whitney officially but called something else in one ep.
* ''Series/{{MASH}}''
** For most of the series, it's made clear that Hawkeye was an only child and that his mother died when he was ten. In several early episodes, Hawkeye mentions having a sister and that is mother is still alive.
** Henry Blake's wife was named Lorraine, but early episodes have him on the phone addressing her as "Mildred".
** Col. Potter once gave his age as 62, but in his first appearance, he said he lied about his age and joined the army during World War I at 15, which would make him around 50 at the time he arrived at the 4077th.
** Margaret Houlihan once told Col. Blake, "You look like my father did right before he died." Her father, 'Howitzer Al' Houlihan, would later visit the 4077th.
** In one episode, Frank was addressed as "Franklin D. Burns" (consistent with the novel, which listed his name as Franklin Delano Burns) but a later episode said his middle name was Marion.

* In "Arrested", several episodes into ''Series/ModernFamily'''s fourth season, Haley is expelled from college and returns home. She's curiously absent from the next episode, "Mistery Date", and the only mention of her is when her mother says she gets emails from Haley about her nails, implying Haley's still at college.
* On ''Series/TheMaryTylerMooreShow'', Rhoda's number of siblings seem to change every so often, leading up to her spin-off where she only has one sister, Brenda. (not helping is the fact that on TMTMS, we do see Rhoda's sister...only it's a DIFFERENT one named Debbie who gets married when Mary is visiting in New York. We never hear about her or her family again.)

* ''Series/{{ER}}''
** In the first season, Doug Ross mentions at least twice that he has a son. No other details are given about this except the child's age (8) and that he's never even met the boy and doesn't even know his name. This is never mentioned again throughout his time on the series, not even during key storylines when it would make sense--his abusive father resurfacing and later dying, his and paramour Carol's plans to have a baby. What makes this a continuity error is that at one point, when asked if he has any kids, he says, "no". The writers either completely forgot about this or decided to drop plans for any further development.
** Also, med student Gallant mentions having a twin sister with cerebral palsy. When she shows up for a visit, it's multiple sclerosis that she's afflicted with.
** Carter is revealed to have had a younger brother who died of leukemia, inspiring him to become a doctor. This is kept consistent. The number of other siblings he has is not. At least one other sibling, a sister, is mentioned a handful of times before Carter officially becomes an only child thanks to his brother's passing.
* ''SuperSentai'':
** In ''Series/TensouSentaiGoseiger'', Agri [[MySisterIsOffLimits gets upset]] at the idea of Moune having a boyfriend, yet in a later episode the team explicitly does not know what romantic love is.
** ''Series/TokumeiSentaiGoBusters'''s early episodes emphasised that Yoko, who had come to EMC at age three, knew very little of the outside world and had never had a chance to spend time around civilians. This is contradicted in a later episode which shows that she attended middle school.
* ''Series/TwoPointFourChildren'': In an early episode, Rona's Aunt Pearl claims to have got married during UsefulNotes/WorldWarII. A later episode reveals that she is [[spoiler:Rona's [[FamilyRelationshipSwitcheroo real mother]]]] and gave her up for adoption in 1957, because Pearl wasn't married "yet" and unwed motherhood was considered a disgrace at the time.

* ''Series/RoundTheTwist'': between seasons two and three, the main characters actually get ''younger'', to the point where two of the kids are one year younger than ''when they moved into town''. Then there's Nell, who was "never married" early on, and in another episode time travel involves meeting her future husband who was manning an observation post during World War II.

* ''{{Series/Supernatural}}'': Sometime in season 8 or 9, the writers somehow got the idea that Reapers were a type of angel, even though they had always been treated as two entirely unrelated species prior to this and it caused numerous problems with previous plots involving Reapers.
* In a flashback in ''Series/{{Forever}}'', Abe gladly goes to fight in Vietnam, but a later episode shows a photo from his days as a student protester.
* While ''{{Series/NCIS}}'' is usually fairly good about this for a long-running police procedural, there are a few occurrences, such as in "Frame Up", where Gibbs states about Tony's service and arrest record "Eight years, three different forces. There's a lot of people who hate you." while in fact Tony has only served in two 'forces' - the police department and NCIS. This could be {{handwaved}} by saying that Gibbs was referring to the three different police departments Tony has served in, but the context would suggest otherwise.

* ''Series/AgentsOfSHIELD'': "Paradise Lost" has a flashback in which a young Gideon Malick and [[spoiler: his brother Nathaniel]] visit Werner Reinhardt in prison. They refer to Reinhardt as Daniel Whitehall, his present-day alias, which he did not begin to use until after he was freed.

* ''Series/GreenAcres'' has at least three different flashbacks to Oliver and Lisa's first meeting: one set on an ocean liner, one in which Oliver is a pilot in WorldWarII landing in Hungary, and one in which Lisa is the daughter of the King of Hungary. The last one was {{Lampshaded}} by Oliver, who doesn't believe Lisa is related to royalty.

* ''Series/TwoPointFourChildren'': In an early episode, Rona's Aunt Pearl claims to have got married during WorldWarTwo. A later episode reveals that she is [[spoiler:Rona's [[FamilyRelationshipSwitcheroo real mother]]]] and gave her up for adoption in 1957, because Pearl wasn't married "yet" and unwed motherhood was considered a disgrace at the time.

** In one episode, Lieutenant Disher mentions that he doesn't have any uncles. A few seasons later, and episode revolves around him inheriting his uncle's farm.

** Also in ''Series/StarTrekDeepSpaceNine''; in one of Ezra Dax's early episodes where she's having trouble dealing with the responsibilities of being Dax's host, Sisko taunts her by suggesting she can return to Trill and become one of the caretakers of the immature symbioties. He then goes on to describe that her duties would entail stirring the mud in the vats which contain the immature symbioties. The trouble is that we've already seen the subterranean caverns he's talking about, and the immature symbioties swim around in immense subterranean rivers, not mud.

** In their first appearance, the Ferengi were aggressive, militaristic imperialists. In later appearances, they are portrayed as craven, greedy people with few cultural arts outside peddling and trading. This was an AuthorsSavingThrow; they'd planned to make the Ferengi the new [[BigBad Big Bad Aliens]] of the franchise, and they didn't realize until the episode was already wrapped and aired that they'd utterly failed at it. So they cut their losses, rewrote the Ferengi (and changed their uniforms to something less silly), and brought back the [[MagnificentBastard Romulans]].

* ''Series/TerminatorTheSarahConnorChronicles'' has a serious timeline inconsistency surrounding the episode "Alpine Fields". The episode has two separate time-frames, one featuring Derek Rees attempting to deliver a wounded pregnant woman's baby in what is implied to be the episode's "present", and the other with Sarah trying to protect the same woman and her family from Terminators during an earlier stage of her pregnancy. The problem is that the woman isn't visibly pregnant at all in the earlier time-frame, suggesting that months have passed between the two sets of themes. However, the events of the entire two seasons of the show don't seem to last that length of time, and a scene in the later episode "Ourselves Alone", involving the question of whether Sarah has a firearms licence, suggests that the entire show up to that point has taken place in a time period of less than thirty days!

* While "{{Series/NCIS}}" is usually fairly good about this for a long-running police procedural, there are a few occurrences, such as in "Frame Up", where Gibbs states about Tony's service and arrest record "Eight years, three different forces. There's a lot of people who hate you." while in fact Tony has only served in two 'forces' - the police department and NCIS. This could be {{handwaved}} by saying that Gibbs was referring to the three different police departments Tony has served in, but the context would suggest otherwise.

** The vanished outposts in the first season finale, "The Neutral Zone", were meant to be foreshadowing of the Borg (In "Q Who?", they encounter an identical pattern of destruction after Q displaces them), implying that the Borg were probing the edge of Federation space even before Q made formal introductions. This is never mentioned again, and Guinan would later claim that, thanks to Q's intervention, the Borg discovered humanity centuries sooner than they ought to have done.

* In the first two seasons of ''Series/PersonOfInterest'', Harold is mentioned to have created a false identity to attend MIT in 1976, and to have hacked the Arpanet with a home-built computer in high school. A flashback in the third season shows a young Harold hacking the Arpanet while still living at home in Iowa - in ''1981''.

** In one episode, Sheldon admonishes Leonard for ending a sentence with a preposition. Anyone with even a cursory ability to recognise grammatical structures would remember that Sheldon has never been averse to this. This may be because the writers [[ViewersAreMorons didn't think anyone would notice]] when they came up with the gag, or because the writers didn't know anything about the "taboo" of ending sentences with prepositions until they wrote that gag and then promptly forgot about it afterwards. On the other hand, Sheldon has often been proven to be a hypocrite, so the error is completely in line with his character.

** The show has two different origins for the Loch Ness monster -- an alien cyborg and a mutated overlord thrown back in time. Similarly, there has been at least three and up to five monsters who are {{Satan}} - Azal ("The Daemons"), Sutekh ("Pyramids of Mars"), the Beast ("The Satan Pit"), arguably the Black Guardian (the Key to Time {{Arc}}) and Scratchman depending on whether you want to consider an [[DevelopmentHell unmade]] film part of the Whoniverse or not.

*** Indeed, in his first appearance in season 2, Michael Zbornak is explicitly stated as being 29 years old, while in the season 3 episode where he reveals he's marrying an older woman, he's explicitly stated as being 23 (Lorraine is 44). In his last appearance in season 5, his age is again explicitly given - this time as 30.

** Indeed, in his first appearance in season two, Michael Zbornak is explicitly stated as being 29 years old, while in the season three episode where he reveals he's marrying episode where he marrying an older woman, he's explicitly stated as being 23 (Lorraine is 44). In his last appearance in season 5, his age is again explicitly given - this time as 30.

* Okay, we all know ''Series/MorkAndMindy'' was pretty much just a fun show about an AmusingAlien who learns something about Earth every week, and even more so it was [[TheCastShowoff an excuse to have]] RobinWilliams [[HarpoDoesSomethingFunny show off his improv]]. But there are just some things that cannot be excused by RuleOfFunny. Such as the season four episode "Three the Hard Way" when Mork [[MisterSeahorse "lays" an egg out of his stomach]], he reminds Mindy that he is a test tube child without a navel, and then displays the navel that was formed when the egg came out. But in the ''first season'' episode "A Mommy for Morky", Mork, mentally aged to a toddler lifts up his shirt and says "I know where my bellybutton is!". And it's there. He was already established as a test tube child, but it's there. And Mindy damn well saw it. And the writers damn well ignored it apparently.

* In the first two seasons of ''PersonOfInterest'', Harold is mentioned to have created a false identity to attend MIT in 1976, and to have hacked the Arpanet with a home-built computer in high school. A flashback in the third season shows a young Harold hacking the Arpanet while still living at home in Iowa - in ''1981''.