Continuity mistake: When the security man gets tossed by the Borg, as he lands and rolls next to the far wall, his phaser falls out of the holster, and lands next to his shin. A second later, it's about two feet away from his leg.
Remember Me - S4-E5
Other mistake: Toward the end, Beverly gets in the turbo lift to go to Engineering. As it starts, you see the lights to her left strobe top down. This is to indicate movement. However, since the lift was at the bridge level, the lights should have gone from bottom up, showing that the lift is going down.
Continuity mistake: While Tam is talking to Deanna and sits down, he says "You understood... at least a little, how I felt." While saying this, he places his left hand on his right leg. While still saying that same line, it cuts to an angle from beside Deanna and his left hand is suddenly between his legs.
Continuity mistake: To view their orders and mission, Data puts a drive into the Enterprise's computer while standing with Riker and Geordi. Riker is seen standing but leaning casually away from Data on Data's right, and Geordi is standing off to Data's left. It then cuts show the computer screen, and the three men are reflected in it. The reflection shows that Riker is suddenly almost leaning over Data's shoulder, and Geordi has moved to standing behind Data's left shoulder.
Revealing mistake: Just after Riker and Geordi are talking in the turbo lift, it cuts to a view from outside the ship and shows the USS Hood flying next to the USS Enterprise. As the ships draw nearer, the views of both ships overlap, and a black mat outline can be seen around the saucer section of the Hood as it passes by the Enterprise's starboard nacelle.
Continuity mistake: In the beginning of the episode, right after Data informs Picard that the USS Hood is on an intercept course, closing at high warp, Picard is shown in the back ground looking down at his arm rest. He looks up and turns his head to his right making it center with his body. It then cuts to a close up of Picard and he is looking to his left, and turns his head again to say "That's odd."
Continuity mistake: When Riker approaches his "son" he raises his right hand to calm him. When the camera angle changes he is suddenly raising his left hand.
Continuity mistake: When Deanna is trying to seduce Riker, she scratches him and there are three deep scratches on his neck. Later, when Doctor Crusher treats him, one of the scratches is now on his cheek, and only two are on his neck.
Other mistake: When Ro Laren enters the Jeffries tube, she makes a sudden shift to her right (our left) as she begins crawling; she was trying to avoid the camera.
Yesterday's Enterprise - S3-E15
Other mistake: The Klingons ordering the Enterprise to prepare for boarding parties doesn't make sense. La Forge had announced only moments earlier that the Enterprise was on the verge of a warp core breach. The Klingons' ship's sensors should have been able to detect the Enterprise's impending destruction.
Conspiracy - S1-E25
Other mistake: When Riker is knocked into the glass table, he should have been bleeding from the impact, but when the close up shows him unconscious, he is not.
Revealing mistake: When the first villain hits Worf with the chair, just as Alexander is yelling "look out", you can tell it is a stunt double.
Encounter at Farpoint (1) - S1-E1
Other mistake: As the Enterprise starts to turn to starboard (right) to escape the energy field Q set up, as the field is moving to port (left, indicating the ship is turning right) the starfield is also moving right, when it should be moving left.
The Battle - S1-E9
Other mistake: When Capt. Picard gets beamed from The Stargazer back to The Enterprise at the end of the episode, he doesn't lower shields. Also, a Ferengi (DaiMan Bok) beams off the Stargazer onto his Ferengi ship earlier without lowering shields on the Stargazer. (00:35:45 - 00:44:20)
Continuity mistake: In the Engine Room, after Geordi calls Wesley and Data, Wes turns around and drops his hands. In the next shot, his hands are back up in front of him.
Suggested correction: Which episode is this for?
Data's Day - S4-E11
Revealing mistake: When Data asks the replicator for Feline supplement 74 and gives then gives it to Spot, a bug is crawling on the food. Replicators cannot create living organisms. (00:13:15)
The Arsenal of Freedom - S1-E21
Revealing mistake: As Data ducks to avoid the blast from the probe, the scene shifts to a wide shot. After Data tosses Yar to safety, he jumps after her. As he does, you can tell it's a stunt man with a bad wig.