Continuity mistake: When Potter goes onto the bus he has his arms down. When in cuts he has his right arm in his pocket. (00:08:45)
Continuity mistake: As Harry walks toward the Monster Book of Monsters as it lies on the bench in the first shot, the bench is near the edge of rug close to the fireplace. As the book chases him the bench is nearer the center of the rug. (00:15:00)
Continuity mistake: Outside Hagrid's when Cornelius Fudge says, "...shall be executed this day at sundown." you see Harry, Hermione and Ron hide behind some pumpkins. You can also see a crow standing on a pumpkin right in front of them. When it cuts from behind them that crow is gone. (01:22:45)
Continuity mistake: In the Shrieking Shack, when Harry sends Snape flying into the bed, the canopy collapses in the stunt. In this shot the metal bars at the top of the canopy frame are visible, whereas in the following shots it is no longer there. The way the canopy frame actually hangs after stunt differs considerably and the draperies hanging on the bed differ in the shots prior, during and after the stunt. (01:33:55)
Continuity mistake: In the paddock scene, Harry is walking towards Buckbeak. The shot then focuses on Hermione putting her arm on Ron's shoulder. Then the camera focuses back on Harry and in the background you can see Hermione placing her arm on Ron's shoulder again. (00:33:10)
Continuity mistake: When Harry is on the Knight Bus, Stan Shunpike has acne on his neck that keeps changing. Sometimes there is a whitehead, and other times it's just a red mark.
Continuity mistake: When they discover The Fat Lady is gone from her painting as the Head Boy says "Let me through. Excuse me, I'm Head Boy." you can see Potter, Hermione, Ron and Neville change position between the shots. (00:45:55)
Continuity mistake: After the incident with the Whomping Willow, the dirt smudges all over Harry and Hermione's clothes change appearance and/or position in the following shots. (01:29:30)
Continuity mistake: When everyone, except Harry, leaves to Hogsmeade village, Hermione is waving as she and Ron walk directly behind McGonagall, with the last of the crowd of children ahead of them still in the courtyard. There is a short cut facing Harry now standing IN the doorway. Then the next shot from behind Harry, shows Ron and Hermione still walking past the fountain, but now McGonagall and the entire crowd of children are out of the courtyard. They could not have walked away that fast. (00:43:35)
Continuity mistake: When Hermione and the others are in Hagrid's hut, a rock with a swirl on it hits the pot. Later, when Hermione and Harry are reliving the scene from the exterior view, Hermione picks up the "same" rock to throw at the pot. The rock is different though, it has a bigger swirl on it. (01:24:55 - 01:51:15)
Revealing mistake: In the scene at night, when Harry is in the hallway with the map, the tip of his wand lights up. And later in that same scene, when Snape has the conversation with Lupin and Harry, Snape's wand does the same. However, if you look closely at the shadows on their faces, they're being lit from above, not from the wands' light below them. (01:13:45)
Continuity mistake: During the scene where Snape confronts Harry roaming the hallways at night with the Marauder's Map, the position of the pull strings hanging down from Harry's sweatshirt hood changes several times between shots. At first the strings are tangled together, but during later shots the strings are hanging down apart, then back to being tangled, then apart again. This happens once more when Prof. Lupin and Harry are talking immediately afterwards in the Dark Arts classroom. (01:13:05)
Continuity mistake: When Marge turns upside-down, just before floating out the dining room door, the bottom of her jacket falls towards her arms and the back of her jacket is deliberately pinned to her blouse and skirt, so as not to fall entirely down. (00:05:15)
Continuity mistake: When the Weasleys give Harry the Marauders Map, Harry takes it from George with his left hand, yet in the next shot the map is in his right hand. (00:57:10)
Revealing mistake: At Hagrid's lesson, just after Malfoy wound Harry up, there is a close up on the class when they first see Buckbeak and you can see Emma Watson holding back a laugh. Surely if her friend was being picked on it wouldn't be funny, plus they're supposed to be scared of Buckbeak. (00:32:05)
Suggested correction: Not true. I saw this scene several times and I never saw Hermione holding back a laugh.
Continuity mistake: As everyone watches Aunt Marge start to soar up into the air while in the yard, the position of the white lace tablecloth, which hangs off the table at this point and the things upon it, differ in the exterior shot looking in towards the dining room and the following interior shot of the table. (00:05:55)
Continuity mistake: When Potter is learning the Patronus charm, as he is facing the candle and is talking about his memory and saying "It's the happiest I've ever felt.". His hair has an extreme change in the next shot. (01:07:10)
Continuity mistake: As Potter is walking back to Trelawney with the ball, as he enters the room through the tight passage, you can see light is shining in. When it cuts to him entering the room the light is gone. (01:17:35)
Continuity mistake: After saying goodbye to Harry, Sirius climbs onto Buckbeak and Hermione hands the chain to Sirius. In the next shot Sirius holds the chain differently. (02:04:15)
Audio problem: When Harry finally pets Buckbeak and the class and Hagrid are applauding, Ron says "Does he get to fly?" but his lips aren't moving. (00:34:15)
