Continuity mistake: In the scene were Mrs. Norris is found petrified, there is a shot of Snape's face and his hair goes down to the middle of his cheek - the rest of his hair is layered like usual. In the next shot of Snape, his hair is longer, almost down to his chin. (00:46:20)
Continuity mistake: In the scene where Harry is stabbing Tom Riddle's diary for the last time, he closes the book and we see a close up of its cover, covered in ink. In the next close-up of the diary its cover is clean, and a small blue dot (where the ink subsequently squirts from) is visible in the centre for Harry to aim the tooth at. (02:15:45)
Continuity mistake: When Dobby stands on Harry's desk, in the close-up he slams the lamp base into his head with the electrical cord coming out of the base to his right. Yet in the next close-up the cord comes out of the base directly in front of Dobby and is now wrapped around Dobby's neck. (00:05:25)
Visible crew/equipment: When Harry and Ron are getting chased by spiders while in the Ford Anglia, you can see a cameraman's shadow on the car (just after they spin around and Harry yells 'Go.').
Continuity mistake: When the car flies towards the Whomping Willow, Ron holds the wand as both of Harry's hands desperately try to steer the car. Yet in the next shot facing the Whomping Willow, only Ron's hand is visibly on the steering wheel. Then in the next couple of shots Harry is still gripping the steering wheel trying to avoid the tree. (00:26:30)
Continuity mistake: When Harry stabs the basilisk through the roof of the mouth, he pulls his arm out and the fang is not in his arm. Yet a few frames later it appears.
Continuity mistake: In the girls' lavatory, when Harry inspects the sink that Moaning Myrtle points out, the pattern of the stains on the porcelain are all visible. However, when the sink descends the stains are actually different. (01:57:55 - 01:58:55)
Revealing mistake: From within the Quidditch pitch, when facing one set of three goal posts the last spectator tower to the left is Ravenclaw and Gryffindor tower is last to the right and when facing the other set of goal posts Slytherin tower is last to the left and Hufflepuff tower is last to the right. After the Bludger breaks Harry's arm, in the shot facing the Snitch, as Harry's hand reaches for it, directly in FRONT of Harry are the goal posts between Slytherin and Hufflepuff towers. Then in the next shot facing Harry, as he reaches and catches Snitch, those same goal posts are directly BEHIND Harry. Yet, when he lands in the sand, he is at those very goal posts. (00:57:20)
Continuity mistake: When the Basilisk emerges from the water, in the first shot Harry looks at the Sorting Hat and Gryffindor's sword appears. As Harry gets the sword, in the second shot the Sorting Hat is not only positioned differently it is also lying on another part of the 'stone' floor. (02:12:30)
Revealing mistake: When Lockhart pushes up Harry's sleeve before attempting to mend Harry's broken bone, we see a few freckles on Harry's forearm. When Lockhart got rid of Harry's bones, he also got rid of Harry's freckles. The freckles are back when Harry drinks the Skele-gro at the hospital wing. In other words, the fake arm was missing details visible on Harry's arm. (00:58:12)
Other mistake: When Fawkes carries Lockhart, Ron, Harry, and Ginny out of the Chamber, you can see their shadows on the rocks. Fawkes' shadow is also visible, but his flapping wings aren't seen.
Audio problem: In the Chamber of Secrets, Riddle says, "You'll find I can be very persuasive." In the next shot facing Harry, the side of Riddle's face is visible and he is obviously speaking before we hear these words, "Not that she knew what she was doing." (02:05:55)
Revealing mistake: When Harry and Ron finally get to Hogwarts, they are flying over a lake. The lake reflects Hogwarts, but not the car, which is closer, and directly over it. (00:26:00)
Continuity mistake: After transforming the bird into a water goblet, Professor McGonagall says, "Now it's your turn. Who would like to go first?" The Slytherin girl on the left has pigtails that start at her earlobes, though in the next shot the pigtails start much higher, at the top of her ears. (00:48:35)
Continuity mistake: In Hagrid's home, when Lucius Malfoy holds out the order of suspension for Dumbledore to take, in the shot facing Malfoy the stiff ribbon ends point in his direction, yet, when the next shot faces Dumbledore, the ribbon ends now point towards Dumbledore. (01:40:15)
Continuity mistake: While in the Whomping Willow, the center point of the cracks and spider cracks around it on the car's windshield changes shape and position. In the first shot of the windshield being smashed to four shots later of Harry turning towards the back, with the windshield visible behind him. Regardless of whether more damage occurs to the windshield, the center point of each of the two cracks should be in the same place, which it is not. (00:27:15)
Other mistake: In the beginning of the movie, when Dobby is hitting himself with the lamp, you can clearly see that the first swing stays a few inches from his head, but he still grunts and shakes his head in pain. (00:05:20)
Continuity mistake: At the Weasleys, there is a close-up of Harry's face as he watches the fry pan being washed. In this shot as Harry walks away, twin 1 removes his jacket, while twin 2, wearing his jacket, closes the window atop the short door. In the next shot as Harry nears the clock, twin 1 takes his jacket off again. (00:11:00)
Continuity mistake: In the hospital wing, as Madame Pomfrey removes the skull bottle top of the Skele-Gro and sets it down, she says, "But it'll be painful," and Harry actually smirks at her. In the next close-up, as she pours some Skele-Gro into a glass and places the bottle down, the skull top now faces the opposite way. In the following shot as she hands Harry the glass, the position of both the skull top and the bottle of Skele-Gro are quite obviously different than the previous close-up. (00:58:55)
Revealing mistake: In the scene when Harry and Ron come back to the bathroom after drinking the polyjuice potion, they find Hermione turned into a cat. Look at her eyes. When she turns around, a digital editing oval appears around her eyes for the rest of that shot.
Chosen answer: After Harry hands it to Lucius, Lucius hands it to Dobby to carry. After Dobby is freed by the hidden sock and protects Harry from Lucius, Lucius leaves it behind.
Greg Dwyer