Plot hole: The car was tracked down by finding the original car key on Jimmy's body. If he had stolen the car from the original owner, how did he come to have the original car key?
See One. Do One. Teach One - S1-E1
Revealing mistake: When they find victim #2 in the woods covered in leaves, in almost every shot of her you can see her breathing - leaves moving up and down. In the closeup of her neck, you can see her swallow.
Character mistake: The registration number of Alan Salt's car is HUA222B, but when Rachel is on the phone asking an officer to look up the car's registered owner she gives the registration number as B222HUA.
Continuity mistake: When Bauer walks up the stairs in front of Waterloo station, the clock on the building is displaying 1:50pm, however we are only about 8 minutes into the episode. (00:07:50)
Here There Be Monsters - S1-E10
Plot hole: The female police officer has a theory that Johnny was the Strangler in the case the papers claimed he helped solve but this hardly makes sense. If she was researching him as was seen in the episode, surely it would have said something about Johnny being in a coma during the bulk of the murders since the story was about Johnny.
Eyewitness - S1-E12
Continuity mistake: When the immortal who's trying to kill Tessa snipes at her in Duncan's car, his shot shatters the passenger-side window. When Duncan tails Tessa and her police escort to the safehouse, the passenger-side window is intact. (00:30:05 - 00:35:50)
Factual error: Jonah tells Richard that Saturn has a "rogue moon" in a retrograde orbit that travels "at four times the speed" of Saturn's other moons. The graphic on Jonah's computer shows that the moon in question is Phoebe, which does indeed orbit in the opposite direction from other Saturnian moons. And the graphic correctly shows Phoebe's orbit as being much further from the planet than the other moons. However, as a direct consequence of its greater orbital radius, Phoebe is actually among Saturn's *slowest* moons. It has a longer orbital period (or "month") and a slower orbital velocity than all the Saturnian moons with smaller orbital radii, of which there are twenty.
Continuity mistake: When Bug speaks with the beautiful widow the second time, about performing a noninvasive autopsy on her husband, her long hair continually changes position in the shots that face her.
Factual error: There is no physical way that Steve Austin could perform most of his superhuman feats of strength in the ABC television series, due to the fact that they simply replaced his arm and legs, but didn't rebuild or reinforce the rest of his skeleton and muscles to handle the physical loads. Interestingly, author Martin Caidin (creator of Steve Austin in his novel, "Cyborg") actually did describe an incredibly complex whole-body rebuild that included vertebral reinforcement and ribcage and pelvis replacement, which was far more scientifically-accurate than the subsequent ABC television interpretation. ABC only accepted the series on the condition that it was less technical for their audience.
Visible crew/equipment: In "Don't Pet the Teacher", when Jeffrey Stone talks to Albert the janitor, a boom mic briefly dips into the shot over Jeffrey's head. (00:06:10)
Kingdom Come - S1-E6
Other mistake: At the start of chapter 12 in the episode "Kingdom Come," Frank returns home via taxi. In front of his house in Seattle, WA, there is a blonde woman walking a Rottweiler dog. This same blonde and Rottweiler can be seen walking by the crime scene in San Francisco in the "Gehenna" episode.
K is for Kill: The Tiger Awakes (1) - S2-E8
Visible crew/equipment: Steed is seen driving along with Purdey and Gambit in rural France. The camera was probably mounted on the front passenger side door, pointing in. As they near their destination, the camera pans to reveal a farm house, and as it pans, a professional-looking microphone can be seen sitting on the dashboard.
Continuity mistake: "Railway Station" (Adventure 2, Part 4): Steel's crooked bow tie straightens itself out between takes as he's confronting the soldier's ghost. (00:04:00)
Tomorrow's So Far Away - S1-E3
Continuity mistake: At the end when Hannah is sitting talking to Caroline's headstone, when the shots change from filming her from the right to the left, the wind is different blowing her hair in one and not the other.
Continuity mistake: The packages Drake and Kathy place on the table beside their coats have disappeared when they return for the coats a few shots later. (00:19:00 - 00:21:20)
Continuity mistake: When Red Buckley is about to enter Emil Duval's house at night before discovering the black pearl, the lights inside the house are on, but when he finally enters the house they are off. Later when he goes out, they are on again.
The Best Years of Your Death - S1-E3
Plot hole: In the chapel, you can see the heads of those who tried to cross Harriet (the mad matron) preserved in formaldehyde. How did she get hold of so much of it? Wouldn't her husband or the headmaster be suspicious?
Water's Edge - S3-E3
Factual error: Pete Taylor's corpse is a bare skeleton after just two years in the sea-shack's attic, though it shouldn't be. There should at least be traces of hair and clothing surrounding the bones. (00:40:00)
Blood Drive - S2-E6
Character mistake: Zayday makes incorrect statements about blood types. She mentions that, since Chanel #5 is type O-, her parents must also be O-; in actuality, they could each be type A or B (genotypes AO or BO, respectively) and could also have Rh+ blood as long as they also carry the recessive Rh- allele. Zayday also says that the child of two O+ parents must be O+, but actually the child could also be O- (again, if the parents carry the Rh- allele).