Continuity mistake: When Scully walks into Mulder's office, she stops in the position with the "I want to believe" poster in the background, then she takes a couple of steps to make acquaintance with Mulder, and she finds herself again in the position with the poster in the background. (00:05:15)
Continuity mistake: When Mulder and Scully are driving after their plane lands, we see at one point that Mulder has his left hand on the wheel and he is eating a sunflower seed with his right, yet when the shot changes he's driving with his right hand and eating with his left. (00:09:45)
Continuity mistake: In the shot taken from the front of the car Scully touches her hair with her right hand, while in the next shot her right hand rests on the car’s door. (00:10:00)
Continuity mistake: When Scully is in her room after the autopsy, we see the x-ray attached to her lamp. When we first see it, we can see the letters LD on it, yet when the shot changes back to the x-ray after Mulder has gone, we can only see I, presumably the other x-ray is now overlapping it. (00:15:20 - 00:16:10)
Continuity mistake: When Mulder, Scully, and Dr Glass stop, in the first shot Mulder’s hands hang down and the doctor’s are in his pockets, while in the next shot Mulder’s hands are rested on his waist and the doctor’s hang loosely. (00:17:05)
Continuity mistake: When Mulder and Scully are arguing outside the hospital, after meeting Billy and Peggy, there is a woman in a red coat, behind Scully, who gets out of her car and then vanishes between shots. (00:19:30)
Continuity mistake: While Mulder and Scully are in the woods, in some shots it is raining, while in others there is no sign of the rain. (00:21:00 - 00:23:15)
Continuity mistake: The place Mulder and Scully find the “X” sign is different from the place Mulder originally painted it (e.g. leafy bush, no fence etc.). (00:23:55)
Continuity mistake: Mulder says that his sister “just disappeared from her bed one night” which is not true, because later visualizations of that moment show that Samantha was abducted while she and Mulder were playing a game and watching TV. (00:26:30)
Revealing mistake: When Mulder and Scully are talking to Theresa at the diner she suddenly gets a nosebleed. If you look closely at her forehead/nose you can see the flesh coloured tube that pumps the blood. (00:33:20)
Continuity mistake: Filmed from the front, Scully nods down but in the next shot when filmed from the back she still keeps her head straight and only after a while she nods it down. (00:34:20)
Character mistake: Scully says that it was Teresa Nemman who was summoned into the woods tonight, while in fact it was Peggy Odell. (00:35:00)
Deep Throat - S1-E2
Visible crew/equipment: When Mulder and Scully attempt to interview Col. Kissell, as he gets out of his car, you can see a square light reflector screen reflected on the car door. (00:12:37)
Deep Throat - S1-E2
Continuity mistake: When Mulder gives Scully the map obtained from the bartender, she holds it in her hand in different ways in each consecutive shot. (00:14:40)
Deep Throat - S1-E2
Continuity mistake: Face-on Scully rests her elbow on the car side window frame with her wrist waving freely, while in the back shot she grabs the handle over the window (this error repeats at least three times in a row every time the shot changes). (00:20:20)
