Corrected entry: When Harry and Hermione watched their past selves from the wood, there were some scenes where events happened too fast in second scenario. They see Lupin say "Immobilis" and the Whomping Willow stops moving, then just a few seconds later they see Snape coming. But the first time, Snape arrives in the Shrieking Shack few minutes after Lupin. Also Lupin transforming into a werewolf is too short in the second scenario. Hermione howls a few seconds after he changes, but the first time, Lupin transforms, then he fights with Sirius for about a minute.Feather
Corrected entry: In the scene where Snape takes over the Defense against the dark arts class, (about werewolves) when the projector changes slides, on the screen the image moves clockwise at the top. However, when you see the projector, the light enabling a picture to be projected is on the bottom and the slides rotate counter clockwise.kevkevtheman
Corrected entry: In the very beginning, Harry is performing the Lumos spell in his bedroom. He's underage, therefore he should be well aware that he's breaking the secrecy rule and should have been alerted to the Ministry, yet they only take notice of him when he 'blows up' his aunt.HulkObsessedChick
Corrected entry: Hermione says that Harry wouldn't want to run into himself in the past, that he'll go mad. There have most likely been many instances when something like that would happen, a polyjuice user encountering the sample, for instance. It would probably cause confusion, but it's very unlikely that someone would go insane as a result.Knever
Corrected entry: When Peter Pettigrew is seen on the Marauder's Map, his dot's footprints are displayed as that of a human's even though he is in his rat form. However, during the credits Sirius' dot is shown changing from human footprints to dog pawprints and back again. Either Peter's prints should've shown up as rat prints or Sirius' should have consistently been shown as human prints.
Corrected entry: Platform Nine and Three Quarters is supposed to be a secret platform that only magical people can access. However when Harry, Ron and Hermione have boarded the train and are looking for a cabin we can see out of the window a GNER (Great North-Eastern Railway) train visible on the next platform. The train is most noticeable for its blue colour with a single red stripe running the length of the train.Scrappy
Corrected entry: When the Dementors are boarding the train, everything starts to go cold, so much so that the water on the windows starts to freeze, and even more noticeably the water in the bottle completely freezes. Once the Dementors have gone, the windows are completely free from ice and the water in the bottle has melted again. This is not possible in the short space of time that passed.Scrappy
Corrected entry: At the Leaky Cauldron a guy picks up a bottle and wraps a rag around it. A second later the bottle is gone.
Corrected entry: When the Hogwarts Express stops and Ron turns to look out the window, Hermione says "Ouch Ron, that was my foot". However, in the next shot, Ron's feet are nowhere near Hermione's. He would have had to have been leaning in order to reach her foot, and he's sitting up pretty straight, too fast for it to change in one shot.
Corrected entry: When the entire school is banqueting after their arrival, D. Malfoy says: "Potter. Is it true you fainted. I mean you actually fainted?" In the book, he found out because Neville was in the compartment as well, and he told "nearly everyone." But, in the film, only Harry, Hermione, Ron, and Professor Lupin are in the compartment. The three friends wouldn't have told them, and a schoolteacher doesn't go around telling such things to students. So, as Harry himself asked, how did Malfoy find out?