Continuity mistake: When Errol drops the howler it lands in a bowl of potato chips/crisps. The seal to the envelope is open, but when Ron grabs it the seal is closed. (00:34:00)
Continuity mistake: When Myrtle is flooding the girls' bathroom, the tap that later doesn't work (the entrance to the Chamber) is happily churning out water - it's on the side nearest the door, so we see it clearly both times. (01:26:05)
Continuity mistake: In the Quidditch scene, Harry breaks his right arm and cradles it on his chest, but when he is lying on the ground after he falls off his broom, he then leans directly on it when he sits up to get away from the Bludger. In the shot immediately afterward, he has his hand cradled in front of him again. (00:57:40)
Continuity mistake: When Lockhart falls down the hole into the Chamber of Secrets, we hear him hit the ground a second or two later. When Ron and Harry jump down, not only do they take longer to get down, they also slide down the pipe, rather than fall straight down. (01:59:40)
Continuity mistake: When Ron and Harry are escaping from the spiders in the flying car the passenger's side window that broke earlier hitting the Whomping Willow is not broken, you can see Ron's reflection. A minute later you see that the window is broken again. (01:48:40)
Continuity mistake: There is a scene where Harry is talking to Ginny in the Chamber, and he is holding his arm right below the wound. In this shot Harry has blood on his hand. When Ginny notices the wound, Harry moves his hand up to cover it. Now his hand is spotless. In the very next shot, however, Harry has blood on his hand again. (02:16:30)
Continuity mistake: In the scene where Harry, Ron, and Hermione are drinking the Polyjuice Potion, Harry leans toward the mirror and starts to gag or something. You can clearly see his shirt is half-unbuttoned. Then they cut away to another shot farther back. Then they cut back to him, and his shirt is buttoned up, nice and neat. (01:20:20)
Continuity mistake: As Ron's luggage cart/trolley slams into Harry's, Ron's trunk is visible. As Ron begins to flip over in the overhead shot, the trunk has five strips of brown trim - two on the edges and three in the middle. When Harry and Ron moan and get up, Ron's trunk now has four strips of brown trim - two on the edges and two in the middle. (00:22:50)
Continuity mistake: In the scene where Lockhart is attempting to teach students how to cast charms for disarmarment, Professor Snape casts his charms against Lockhart. Lockhart goes flying through the air, wand in hand. The movie then cuts to a shot where Lockharts wand goes flying through the air out of his hands, then cuts back to a shot from his left shoulder where he lands wand in hand. Movie then cuts back to his front left, and he gets up without wand in hand. (01:05:42)
Continuity mistake: When Harry falls out of the car as he and Ron are flying above the train, his hand misses the door handle completely and he should have fallen clear to the bottom of the gorge. However, in the next shot and after, he is hanging onto the handle quite firmly.
Continuity mistake: When Harry cast the charm on Malfoy in the duelling club, Malfoy falls on the floor with is hair messed up. When the camera cuts to the next scene as Snape pulls Malfoy up, his hair is neat again. (01:07:40)
Continuity mistake: When Harry and Ron run into the wall in the train station, you can see the owl's cage break open and topple sideways, but in the next shots, the cage is closed and standing up. (00:22:50)
Continuity mistake: When Ron, Harry and Hermione drink the polyjuice potion, they all drop their glasses, smashing them onto the floor and presumably making a big mess. However, in the high angle shot looking down at Harry, there is no sign of broken glass or any potion splattered anywhere. (01:20:10)
Continuity mistake: When Harry, Dumbledore, and Lucius Malfoy are in Dumbledore's office and Harry says he will be around to save the day, his face is clean. Later, when Harry gives Malfoy Tom Riddle's diary, his face is as grimy as it was in the Chamber. (02:23:25 - 02:24:25)
Continuity mistake: In the shot where Dobby takes Harry's letters from his robe and tells him about why he hid them he is standing in front of the dresser, you can see that the drawers in the dresser are neatly closed (with the exception of the bottom one, which is only slightly open). However, in the next shot when Dobby runs out the door with Harry chasing after him you see the dresser again, and this time all the drawers are slightly open and uneven. (00:06:33)
Continuity mistake: In Moaning Myrtle's bathroom, the mirrors don't reflect at all, they're very dirty. But when Harry changes into Goyle, his face is clearly reflected in one of the mirrors. (01:20:20)
Continuity mistake: In the scene where Harry slides out from the fireplace into this dark shop, he quickly exits through the front door. Just before he walks out, look closely. The sidewalk outside is bright and sunny, not like the dark and dingy surroundings that he walks out to. (00:16:20)
Continuity mistake: In the Chamber, when Harry runs from the Basilisk he ends up at a gated dead end, with steel bars that are embedded in a circular stone wall. When Harry crouches down, as the Basilisk's face nears, the manner in which the bars are embedded in the stone is actually quite different. (02:11:00)
Continuity mistake: While Harry is communicating with Riddle's diary, after the words "let me take you back fifty years ago" appear on the page, the ink pot's lid is open as the diary pages flip and Harry lifts the book, but in the shot from Harry's POV we see the ink pot lid closed, then the lid is open again when Harry's transported.
Continuity mistake: When Ron and Harry crash into the Willow you can see that the Willow smashes the front side of the car and the left light. Afterwards the light is back and undamaged. (00:27:20)
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