Via Negativa - S8-E7
Continuity mistake: When Doggett leaves his office, he reaches for his coat, grabs it and starts to put it on. In the next shot, when Langly, Frohike, and Byers look in Doggett's direction, we again see that he takes the coat off from the chair. (00:27:55)
Trust No 1 - S9-E6
Continuity mistake: When the guy from the NSA is speaking with his supervisor, after the supervisor asks him about his wife and child, in the background he turns his head toward the supervisor, while in the next close-up take he turns his head toward the supervisor again. (00:12:30)
Trust No 1 - S9-E6
Continuity mistake: When Scully is pulling out, in close-ups she holds her cellphone in her left hand, while in distant shots she keeps her left hand on the steering wheel. (00:23:00)
Continuity mistake: When Knowle Rohrer is talking with Agent Doggett face to face in a separate room about the super-soldier project, he is wearing a red FBI badge, but in the previous scene when he came to visit Doggett, he was wearing a regular FBI badge. (00:08:40)
Continuity mistake: When Agent Reyes and Agent Scully are talking about mood music, in some shots Reyes rests her hand on the bed's backrest, while in other shots she firmly grabs it. (00:14:45)
Continuity mistake: When Agent Reyes is aiming at the oncoming car of a ranger, in the front shot the windscreen of the car is completely covered with dirt and fully opaque, while filmed from the ranger's side the windscreen seems to be transparent and relatively clean. (00:17:00)
Nothing Important Happened Today II (2) - S9-E2
Continuity mistake: After entering the room with the water tank Agent Doggett has dived into, the Assistant Director Brad Follmer screams "Doggett!", while in the same scene in the "Nothing Important Happened Today I" episode he screams "Agent Doggett!" (00:03:35)
Trust No 1 - S9-E6
Continuity mistake: When Scully reads the alleged printout of the email sent to her by Mulder, it says: "Dearest Dana: I've resisted contacting you for reasons I know you appreciate...I want to come home, to you, to William", but when Scully has previously viewed this message in the internet café, it had a different form: "I've resisted contacting you for reasons I know you continue to appreciate...I want to come home. To you, and to William." (00:06:05)
Continuity mistake: During the conversation with Mulder, in the front shot the Deep Throat tilts his head to the left while in the back shot his head is tilted to the right. (00:26:10)
Continuity mistake: When Scully enters her apartment, the blinds are up and there is quite a lot of light in the room. However, when the flashback with Mulder ends, during which Scully was supposedly standing still, the shades are rolled down and there is much less light in the room. (00:20:30)
Empedocles - S8-E17
Continuity mistake: When the fiery figure comes up to Jeb, he is standing alone on the street, however in the previous and following take he stands in the crowd surrounded by other people. (00:02:15)
Continuity mistake: In the opening scene, when the guy is calling from the booth, he is standing either on the left or right side of it, depending on the shot. (00:00:40)
Without (2) - S8-E2
Continuity mistake: When Mulder's fall from the cliff is filmed from the ground, one can see that he is wearing white shirt, while earlier and afterwards Mulder is dressed in a grey T-shirt. (00:03:20)
Continuity mistake: The car where the guy is killed is a 1970 Ford LTD convertible in front but a 1969 Ford LTD from the rear.
Continuity mistake: At The End of Max's seizure Mulder holds him under his chin, but in the next shot he holds his hands. (00:26:30)
Continuity mistake: When Michelle is driving her car, the back shots show some label to the left of a driving wheel that is missing in the front shots. (00:15:10)
Continuity mistake: When Michelle's car lays upside down, one can see that it has headlights with two lamps on each side, but in the previous shots her car has only one lamp on each side. (00:15:45)
Continuity mistake: During Colonel Belt's funeral, there are saluting soldiers standing behind Michelle in some shots, while in others they are not there. (00:43:45)
Continuity mistake: When Skinner is stopping Mulder from hitting Krycek, in the back shot Mulder keeps his hand on Skinner's neck, while in the front shot he keeps his hand somewhere else. (00:31:50)
The Goldberg Variation - S7-E6
Continuity mistake: When Henry is hit by a truck, the lower part of his body is located under the vehicle, but when Mulder walks up to him, he is lying beside the truck. (00:32:50)
Answer: As he stated many times throughout the series, Mulder needed Scully to be sober and skeptical. Whenever Scully's skepticism wavered and she started questioning her own rationality, Mulder would try to restore her sense of skepticism, because he needed her to be clear-thinking.
Charles Austin Miller