Continuity mistake: At the Dursley residence, when Harry wakes up and gets out of bed to look out the window, a bowl and plate with leftovers sit on the desk. In the following shots, until Vernon goes after Harry out the window, the food on the plate changes and the plate changes position back and forth on the table. When Vernon yells, "Petunia, he's escaping," in the interior shot the lamp is at the corner of the bed, yet in the next exterior shot it's lying on the pillow. The position of Harry's comforter changes during his escape as well. (00:08:25)
Revealing mistake: When Harry stands at his bedroom window looking at the nearing headlights, the houses opposite him on the left are really the neighboring houses that are seen to the left of the Dursleys when facing the Dursley house and the one on the right is actually the Dursley's home. In the close-up of the car as its headlights face Harry, the Dursley's house is seen behind it, but the check curtains and patio table were added to change the look of the house. The distinctive pattern of each of the home's bricks are a giveaway. (00:08:30)
Other mistake: Harry now has Dudley's toy room and Dudley's is next to his, however when there is a shot outside the house there is only the one window on the left side of the house and not much space between it and the left outside wall, where is the window for Dudley's very narrow room? (00:09:00)
Continuity mistake: After Harry packs his trunk, in the wide shot, as Ron starts to lean over to attach the hook to the bars, the excess rope is in the corner of Ron's window, but in the next close-up it's right in the center. (00:09:10)
Continuity mistake: At Harry's bedroom window, the curved dirt line on the windshield is visible when Ron says, "Let's go," in the close-up, as the Ford Anglia begins to turn. In the next two shots as they pull away, the dirt line is different. When Ron yells, "Come on Harry, hurry up," and Harry passes Hedwig to Ron the dirt line is the same as the first shot. This goes back and forth in the remaining shots at the Dursleys. (00:09:15)
Continuity mistake: When the bars on Harry's window are seen falling in the shot looking up, the windowsill is up on the left side and is visibly very crooked. Yet when the Weasley car backs up to Harry's window, the windowsill is perfectly fine again. (00:09:20)
Continuity mistake: There are eleven vertical front bars on Harry's window, five on each side of the center bar. Ron attaches the hook to the bars on Harry's window and when he says "Let's go!" we see the hook between the third and fourth bar on the right. Yet in the next shot and also in the shot looking up as the bars fall, the hook is between the fifth and sixth from the right. (00:09:20)
Revealing mistake: When the bars on Harry's window are being ripped off, most of the window frame comes off as well. In the close-up. the attached hook pulls the bottom of bars and window outward, causing them to fall a certain way. Yet in the next shot looking up, the way in which the bars and window fall is strikingly different, not to mention unrealistic if it was really being yanked out via the hook at the bottom. (00:09:25)
Continuity mistake: Right at the very start when Vernon grabs Harry's ankle during his escape, his grip on the ankle changes instantly. (00:09:25)
Revealing mistake: The Ford Anglia's front seats keep changing. When Ron, Fred and George are rescuing Harry from the Dursleys, the front passenger seat has a curved thin back and is very dark blue with light blue trim at each side. However some examples when it differs are, as Harry hangs from the car while flying over Hogwarts Express, though the seat has a curved back, in some shots the seat is two shades of light blue and in others it is as in the shots at the Dursleys. Yet at Hogwarts, when the car ejects Hedwig, the back of the seat is thick and perfectly sraight and so on. (00:09:35 - 00:25:05)
Continuity mistake: When Harry escapes into the Ford Anglia, in the interior shot Ron grabs firm hold of Harry under his left arm, while Vernon pulls on Harry's foot. In the overhead exterior shot Ron's arm holds Harry above his arm, yet in the next close-up of Harry, Ron's arm is under Harry's. Then just after Ron yells, "Drive!" Ron's arm is over Harry's arm once again. (00:09:45)
Audio problem: As Harry escapes into the car, Ron leans forward, puts his left arm in front of Harry and although we hear him say, "I've got you, Harry!" Ron's lips remain apart, with teeth are clenched, and his mouth does not move. (00:09:45)
Continuity mistake: When Uncle Vernon pulls on Harry's ankle to stop him from escaping, Vernon's sleeve changes from being ridden up, to at his wrist and then back again in consecutive shots. The amount of pajama sleeve showing under his plaid robe sleeve changes too. (00:09:45)
Continuity mistake: When Harry is in the Weasley's car, Ron yells, "Drive!" and four shots later Uncle Vernon shouts, "No, no, no no no!" when he starts to fall out the window. As the car pulls away from the wall, Harry is not wearing his eyeglasses in this wide shot, though it's on in the previous and following shots. (Most viewers agree that in this shot it is Dan Radcliffe's double in the front seat of the car, who has a longer face than Radcliffe's smaller, rounder face, but that is not the issue of this specific mistake.) (00:09:50)
Visible crew/equipment: When Uncle Vernon falls out of Harry's window, in the interior shot as he yells, "No, no, no, no, no!" leg pads are visible under Vernon's pajamas as his legs fly out the window. (00:10:00)
Continuity mistake: When the car arrives at the Weasley's house, two white ducks are at a small pond, one in the water and one on the bank. From the overhead shot as the car lands, the grass directly around the pond is dry grass and the duck on the grass faces the house. In the next shot from the ground, the grass is very green and that duck faces the other way. (00:10:40)
Continuity mistake: When the car lands in front of the Burrow, it touches the ground just in front of a small shed and passes it within seconds. An angle change then shows the car driving past the same shed. (00:10:40)
Continuity mistake: When Harry, Ron, Fred and George arrive at the Weasley house, first in the wide shot as one twin enters the doorway, then in the next close-up as the rest enter and third, just before Ron takes a biscuit, the amount and arrangement of the biscuits differs in each shot. (00:10:45)
Continuity mistake: When Harry arrives at the Weasley's house, we see a shot of the chimney that he is going to travel up. There is no pot of floo powder nor is there a bracket to hold it. When they go to travel to Diagon Alley, the bracket is on the right of the fireplace attached to the bricks, with the pot of floo powder in it. (00:10:55)
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)
