Continuity mistake: In the early episodes, Geordi's rank is inconsistent. In "Encounter at Farpoint", he is a full lieutenant. In subsequent episodes, he is a lieutenant junior grade, before being promoted back to full lieutenant.
Continuity mistake: In one scene on the planet, Riker's clone is lying under a table fixing something and Riker is sitting in a chair talking to him. There are two camera angles used. In one angle when the clone is talking and a body double is sitting in the chair he is facing directly towards the table but in the other camera angle where you can only see Riker, the chair is at an angle facing towards where his clone is lying on the floor.
Encounter at Farpoint (1) - S1-E1
Continuity mistake: Commander Data tells Picard the Saucer Section will arrive in 51 minutes. Riker's synopsis audio can be heard in the background without interruption, and shortly after Data says this, the cameras turn back to Riker and the Video synopsis ends. Riker immediately reports to Picard who then receives the message that the Saucer Section is in orbit. Now, Riker was watching highlights of video footage from the Bridge, of which we see almost all of it because there really wouldn't be that much to view. And that's really all he could watch since we don't have cameras in the "Q-verse" and we see the footage ending with the Q sphere chasing the ship. Also, the entire ordeal was far less than an hour so there's no way a highlight reel could take an hour, not to mention the uninterrupted audio. We seem to be missing almost an entire hour. (00:37:32)
Continuity mistake: Looking at the shuttlecraft while sitting in the shuttle bay and after it has departed the Enterprise, you can tell they are different types of shuttles. The one in the shuttle bay has more angular lines with straight edges. The one outside the Enterprise has more curves than angles to its lines.
Continuity mistake: When the original Picard shoots the duplicate Picard with a phaser in the shuttlebay, he shoots him square in the chest. But in later shots, the scorch marks from the phaser are on his abdomen area.
The Pegasus - S7-E12
Continuity mistake: In the opening log entry of the first episode, Picard says that "I have been informed that a highly experienced man, one Commander William Riker..." He sounds as though he has been assigned a First Officer without knowing him. However, in this episode he tells Pressman that he read Riker's file, and wanted him, based on Riker's adamant refusal to obey an order that went against his safety protocol.
Suggested correction: There's no error here. Picard likely read the files of many officers and requested the ones he preferred, and Star Fleet informed him which one he would get.
Continuity mistake: With his right arm Data is accessing the holodeck circuitry via the manhole while he is holding back a taxi cab with his left arm. Each time the scene switches to viewing Data from the back you see his right hand in the manhole and eventually his left hand appears. All the while you still hear the sound of the taxi cab. Each time the scene shows Data from the front he is holding back the taxi cab with his left hand.
Data's Day - S4-E11
Continuity mistake: At the end, Picard shows Data a baby born during the crisis. Neither of them touches it, but between shots, the baby's blanket changes positions. First it's almost completely covering his head and face, then it's pulled down and showing much more of him. (00:42:15)
Continuity mistake: Data is driving a pair of brown horses pulling an enclosed carriage. You can see the side of the carriage as it comes around the corner. Next shot, when they climb aboard, it is open-sided. (00:17:40)
Continuity mistake: When Data goes into his laughing fit, Troi is at her regular seat, but when he stops and remarks it was a wonderful feeling, the wide shot of the crew shows her seat empty. But then, when Picard is hailed, when the moon returns to its orbit, Troi is back at her seat.
Continuity mistake: When Lore backhands Worf in the turbolift, his eyes close but open back up as he is sinking down. Then, in the close-up, his eyes are closed again.
Conspiracy - S1-E25
Continuity mistake: Lt. Commander Remmick has three solid pips on his uniform when Admiral Quinn is beamed to the Enterprise, implying his rank to be Commander rather than Lt. Commander. In all other shots in the episode, his rank is displayed as Lt. Commander. (00:25:11)
Continuity mistake: Near the end, after being subjected to the snowy scene, only Mr. Leech has snowflakes on him. They're on him as he steps into the corridor, then they're suddenly gone.
Continuity mistake: When Yar is transported back to the ship her weapon was on her left arm. When on the transporter pad the weapon is on her right arm.
Continuity mistake: In the opening scene, Riker's rank pips are diagonal on his collar. Then in Worf's quarters, the pips are level as they should be.
Continuity mistake: When Data is dealing the cards for 7-card stud, they show him dealing 1 card to everyone. In the close up, he's now dealing everyone a 2nd card. When it cuts to his hands however, everyone only has 1 card and he's dealing them a 2nd card again.
The Royale - S2-E12
Continuity mistake: When Data is first playing Blackjack, his first face up card dealt is a 7, followed by a 5. In the close up when the final card is dealt, the first two cards are now 3 and 2.
Continuity mistake: When Data is telling Guinan jokes and is then called to the bridge, he's holding the cigar between his first two fingers. In the next shot, he's holding the cigar between his thumb and first finger.
The Dauphin - S2-E10
Continuity mistake: When Wesley and Salia are on the holodeck looking at Roseau 5, Salia's left arm is around Wesley's back. In the next shot, both her hands are wrapped around his arm.