Corrected entry: In the scene right after the Quidditch game (when Harry, Ron, Hermione, and Hagrid are walking through the brick tunnel thing) Ron's scarf is like Harry's - one part over his shoulder, hanging in the back, and the other part of the scarf in front. But when they all walk forward more, and the camera gets closer to them, Ron's scarf is hanging over both shoulders.
Corrected entry: When Harry came back down from when he caught Neville's Remembrall, all the other students cheered and ran towards him. Wouldn't half the students stay back and look mad, since half of them are Slytherin? (00:56:35)
Correction: Not all the students in Slytherin hate Harry.
Corrected entry: When everyone is at the end-of-term feast, Harry has a cast on his wrist, but couldn't Madam Pomfrey (the nurse) have fixed it with magic?
Correction: As witnessed in "Chamber of Secrets" (and in the books), Madame Pomfrey can't just wave a wand and heal serious injuries; she can accelerate the healing process with magic, but it still takes some time.
Actually, Madame Pomfrey herself says "I can mend bones in a heartbeat" (in CoS). It is regrowing bones that is difficult and takes time. Assuming Harry's bones weren't removed in his struggle with Quirrell, the injury would have been fairly simple for Madame Pomfrey to fix. And if Snape can mend Malfoy after Dark magic is used in HBP, surely Madame Pomfrey can fix a cut on Harry's arm.
Corrected entry: When Harry, Ron, and Hermione are hiding from Filch, they find Fluffy, scream, and run away. But when they are speaking of it later, Hermione says something like "Honestly, don't you two have eyes? Didn't you see what it was standing on?" But it never shows Hermione looking down at the trap door when they were face-to-face-to-face-to-face with the three-headed dog.
Correction: The scene cuts frequently therefore she could have glanced down when the camera was not focusing on her face.
Correction: They first see Fluffy while looking down, then travelled all the way up to its face. That's when she saw the trap door.
Corrected entry: When Hermione is trying to figure out the Devil's snare she pulls her magic wand out of nowhere and once she uses it and wants to check if Ron is OK the magic wand disappears.
Correction: She pulled it out of her skirt and put it back in the process of kneeling.
Corrected entry: In the scene when Harry, Ron, and Hermione visit Hagrid, Malfoy is visible through the window. He appears to be eye level with the window and is shown turning and running away. When the camera zooms out later in the film, the same window that Malfoy is supposedly looking through is far too high for anybody to see through without a ladder. He obviously didn't have a ladder or he would have fallen off it when he turned to run away.
Correction: It's not the same window - there's no outside view of it, so we can't be sure how high it is.
Corrected entry: In the first scene Professor McGonagall's broach disappears and reappears several times.
Correction: This may be explained by the fact that she is wearing a cape over her shoulders. As she moves her head, the broach becomes less (or more) visible.
Corrected entry: Hagrid appears at the hut on the rock to fetch Harry on Harry's 11th birthday, which is July 31. The next day they go to London to buy Harry's school supplies, then end the day at King's Cross. But the letter Hagrid hands Harry at the hut (in the book, anyway - and in the film if you stop it to read what Harry doesn't) tells him to report to the train on September 1. What happened to the month of August?
Correction: It is never specified when is Harry's birthday This is a film/book discrepancy.
This seems far-fetched as it is way too well known in the HP universe, the date of Harry's birthday, and it becomes very significant to the plot as to why Voldemort targeted him. A more likely explanation is the film didn't actually say they went out for school supplies the very next day. It was just assumed as that was the next scene we saw. For all we know, Harry and Hagrid stayed elsewhere for a month, and the filmmakers considered it insignificant to show.
Corrected entry: In all the shots of Snape that show the area around his feet, his cloak is either dragging on the floor behind him or gathered about his feet showing that it is quite long. However, after he wishes Harry luck in the Quiddich game against Slytherin, when he walks away the cloak is short enough in the back so Harry can see his limp from being bitten by Fluffy.
Correction: He could have had more than one cloak. So when he got the injury on his leg, the other cloak could have gotten ripped so it needed repairing. That meant that he had to wear a different cloak until his other one got mended.
Corrected entry: When Harry visits Gringotts, and is seen at vault 713 he is carrying 3 bags (presumably money he has just taken from his own vault). When he has picked up some supplies, and is just about to go to Olivander's, he and Hagrid are only carrying boxes. (00:23:25)
Correction: Maybe Hagrid was carrying them in his coat, or maybe they had spent almost all the money, so they didn't need to carry the bags.
Corrected entry: The promotional photos show Harry Potter with a scar on his forehead over his right eye. On the covers of all the books, the scar is clearly shown to be over his left eye. This is to correct the mistake about the scar being in the wrong location on Harry's head.
Correction: JK Rowling has commented on this and said that in the text of the books, the scar's location is never indicated (only that it's on his forehead somewhere) and it was the novel's artist who decided that it should be centered (see the 4th book cover for the best view). The movie people decided to make it off-centre, and Rowling was fine with that.
Corrected entry: When the troll is in the girls toilets, it looks like there's only one line of cubicles, and he smashes the top half off twice.
Correction: he only smashed a few of the stalls the first swing, then the rest of them the second time. There is still only one row of stalls.
Corrected entry: Harry Potter has lovely green eyes. When Voldemort is about to kill baby Harry during the flashback, Harry's eyes are blue.
Correction: Almost all Caucasian babies have blue eyes initially - they only change colour as the child gets older.
Corrected entry: When Harry first finds the mirror of Erised, he walks through the door and the mirror is on his right. This is the same when he takes Ron to see it, but when Dumbledore finds him in front of the mirror, if you look where the door should be, there is just wall.
Correction: It took a close look to resolve this one. The room's laid out such that the door is between the outer wall and a shorter inner wall - Harry has to run around it to get to the mirror. As such, when we see the room it looks like the door's disappeared, whereas actually it's just behind a short wall.
Corrected entry: During the Quidditch match, someone falls from their broomstick, landing in a pile of sand. But when we first saw the pitch it was all neat grass - where did the sand come from?
Correction: There's sand visible under the goalposts in the first shot of the field.
Corrected entry: How come Hermione is so confident that she'll get into Gryffindor? On the Hogwarts Express Train, she is already wearing a Gryffindor tie (red and yellow) before arriving at Hogwarts or being sorted into houses.
Correction: She is wearing a black tie with Hogwarts' crest.
Corrected entry: If Harry, Ron and Hermione can walk undetected under the invisibility cloak, why can't Harry walk with the lamp underneath it when he is going to the restricted section of the library? Surely he wouldn't have to hide the light if he did so, reducing the risk of being spotted?
Correction: Two thoughts - one is that he might worry about it catching fire, the other is that it might work on a "one way" system. Light can go into the cloak, so he can see through it, but light can't escape out, so no-one can see him, and similarly the light from the lamp can't escape. If anyone has an official description of how the cloak works, I'll gladly hear it!
Corrected entry: Harry had to pass the key and chess challenges, which caused damage to the door (all the keys flying into it) and the chess set (all smashed up), but when he arrived Prof. Quirrell was already at the mirror. How did he get past them without causing all that chaos?
Corrected entry: It the begining of Harry Potter, there is a sequence when Harry's mother is being killed. When we see Harry, he is wearing a Blue's Clues romper suit - I do not recall Blue's Clues being around 12 or so years ago.
Correction: The pajamas baby Harry is wearing are not Blue's Clues. It's a blue bunny on the sleeves.
Corrected entry: At the battle with the professor, the professor was perfectly fine when he tried to strangle Harry. It's only when he was touched by Harry's hands did he start to melt. But later Dumbledore said that the power was in Harry's skin (But apparently not at the neck).
Correction: The power is in his touch, ie. when Harry uses his hands - it doesn't necessarily apply to any part of his body.
Correction: Actually, the scarf always remains on both shoulders, it's just a bit difficult to see when Ron is far from the camera.