Continuity mistake: At the start of term feast, after Harry is sorted into Gryffindor, he sits down on the right side of the table next to Ron. When the feast appears, Harry is on the other side of the table, next to Hermione. (00:46:05)
Suggested correction: This is not a mistake. In the first shot, Harry was just sorted into Gryffindor and there were still quite a few students waiting to be sorted. By the time of the second shot, all the students were sorted and the feast started. Therefore, at least a few minutes have passed and Harry had plenty of time to switch sides of the table. Doesn't make much sense why he did that, I agree, but still plenty of time to do it.
I agree, but it's not about how there's plenty of time to do it. Like you said before, there's no reason for Harry to change position. Therefore, it counts as a mistake.
Continuity mistake: After Ron is eliminated by the white queen, Harry moves two squares back and stands next to the black bishop. However, after the shot switches to Hermione and again to Harry, the latter now finds himself just in front of the white king, well away from his previous place, at the moment he says 'Checkmate'. Just after this, the white queen can be seen lying next to Harry as the white king's sword falls to the ground; however, she is never heard to fall.
Visible crew/equipment: During the Quidditch match Harry's broomstick tries to shake him off, due to the spell. After Hermione tells Ron, "Leave it to me," in Harry's last close-up before he flips over, the seat that is attached to the broomstick, to make it more comfortable for Dan Radcliffe to sit on, is entirely visible. Glimpses of other seats can be had during the match as well. (01:20:50)
Continuity mistake: At the snake exhibit, while Harry speaks with the Python the snake's body lies curled over a long wood log and a large rock. In the shot from outside the Python's exhibit, after the glass pane disappears Dudley falls over the rail and the snake is gone, not positioned differently or blocked from view, but altogether gone. In the next overhead shot inside the Python's exhibit, while Dudley falls the snake is back lying on the log and rock, in the very same position as in the previous shots. (00:07:10)
Visible crew/equipment: At the Quidditch match, after Hermione sets Snape's cloak on fire and someone shouts, "Fire! You're on fire!" there is a close-up of Harry with his hands gripping the Nimbus 2000. In this shot, the wire rods which are attached/taped to the broomstick, near Harry's fingers, that lead under both of his red sleeves, are entirely visible. (01:21:35)
Other mistake: When Harry, Ron and Hermione rush to Hagrid after the end of the year exams, and Harry is saying something that ends with, "Why didn't I see it before?", Hermione is mouthing part of that line. [Emma Watson did admit she learned Dan and Rupert's lines as well as her own and found herself accidentally mouthing them.] (01:50:40)
Continuity mistake: When the troll enters the girls' lavatory, in the wide shot as Hermione walks backwards towards the cubicles, the room becomes brighter from the storm. With this extra bright light it is simple to see that the wall between the 2nd & 3rd cubicles actually touches the floor, unlike the other cubicle walls. Yet, in the overhead shot as the troll's club slams into the cubicles, Hermione is lying under that very wall crawling away. (01:10:05)
Visible crew/equipment: Being chased by the flying keys, as Harry zips by on the broomstick he tosses the key, Hermione catches it and runs to the door. In the next shot, a close-up, as she tries to unlock the door, an electrical cable hangs down beside the column, that was not in the previous shots. There is also an electrical cable coming out from under the back of Hermione's sweater that is blatantly visible as well. (01:59:55)
Visible crew/equipment: After Quirrell announces there's a troll in the dungeon, Dumbledore shouts, "Silence!" and soon continues, "Teachers will follow me to the dungeons." In the following shot of McGonagall, the wires that the candles hang from are plainly visible. (01:09:00)
Continuity mistake: When the three children get past Fluffy because the harp is playing, as Fluffy wakes he dribbles on Ron's shoulder. However, when they fall down into the Devil's Snare, his shirt is completely dry. (00:51:16)
Visible crew/equipment: Petunia has her hands on Dudley's eyes as they walk towards all of his birthday gifts. When she removes her hands from Dudley's eyes, in this shot and in the next, the long black microphone wire as well as its tape, which obviously peeled free, are blatantly visible and are sticking out at the neckline of her v-neck top under the pearl necklace. It's gone in the following shots. (Do not confuse the blue apron strings for the mic wire.) (00:05:00)
Visible crew/equipment: After falling from the Devil's Snare, Harry tells Ron, "Lucky Hermione pays attention in Herbology." Then as Ron starts to walk toward Harry, there is a crew member's arm and hand gripping the back of Ron's shirt at the bottom. (Visible on DVD fullscreen.) (01:57:45)
Other mistake: When Harry receives his first letter in the mail, Dudley snatches it from him before he has a chance to open it. Then he gives it to his father (Uncle Vernon), and Uncle Vernon says "Who'd be writing to you?" If you watch Dudley carefully, you can see him mouth what Uncle Vernon is saying. (00:08:54)
Visible crew/equipment: In the scene where Hermione, Ron and Harry are returning to Gryffindor's tower room after being in the third floor room for the first time, you are able to see the feet of one of the crew. It happens just as they are passing through the picture hole, where Harry turns a couple of times to check that the "door" is closing. And it is in fact, because someone is walking behind it and pushing it shut, since the picture hangs several inches off the floor. (01:02:55)
Audio problem: During the scene with the "flying" letters Harry gets one letter and tries to go in his "room", but Uncle Vernon grabs him. When Harry yells "They're my letters," not only his mouth doesn't move but his voice sounds much deeper than in the rest of the movie (it sounds more like his voice in Chamber of Secrets). This indicates that this line was overdubbed long after the main filming, when Daniel Radcliffe's voice has already begun to change. (00:11:55)
Audio problem: When the troll is about to swing at Harry for the third time with his club, Ron levitates his club in mid-air. When the club falls, it hits the troll's head with a loud thunk, then falls to the ground. But you never hear any sound of the club hitting the ground. (01:08:44)
Visible crew/equipment: Hermione opens the door to Fluffy's room when she says, "Alohomora!" so she, Harry and Ron could hide from Filch and Mrs. Norris. As Ron closes the door the top of the third floor corridor set is visible at the top of the screen. As an aside, when Ron repeats, "Alohomora!" look at Hermione's face. (01:02:00)
Continuity mistake: During the flying lesson scene, some strands of Hermione's hair have very deep crimps on both sides of her face in a few shots. In other shots the crimps are far looser and still in additional shots, there are no crimps whatsoever. (00:55:25 - 00:57:10)
Visible crew/equipment: After the Queen attacks the Knight's horse during the chess game, Ron goes flying back and falls. In the shot as he hits the ground, the black protective gear that he wears is visible when his grey T-shirt rolls up and the button on his left cuff is open, yet closed in the next close-up. (02:05:15)
Visible crew/equipment: Dumbledore tells Harry that he will move the Mirror of Erised and not to go looking for it. In the following shot Harry walks outside in the snow with Hedwig on his arm. In the close-up of Hedwig, the jess (strap) around his left leg is visibly tethered to Harry's sleeve. The inside of Harry's sleeve also has a strap that secures the sleeve around Harry's wrist. Hedwig is obviously not tethered in the next shot. (01:36:45)
