Continuity mistake: While camping and searching for horcruxes, the size of the trio's tent changes from location to location. Harry is standing beside it while Ron and Hermione are skipping stones across a body of water, and the tent is fairly tall. Other times, it's very short like a pup tent and they must stoop to enter.
Continuity mistake: When Voldemort kills Lily, she is wearing a sweater with high neck, long sleeves and it's red. When Snape comes in the room and sees Lily dead on the floor, she is wearing a blue blouse.
Continuity mistake: When Harry arrives in Hogsmeade and meets Aberforth Dumbledore, his stubble disappears in one shot and then reappears later in the same scene.
Continuity mistake: When Harry, Ron, Hermione, and Neville are in the Room of Requirement talking to Ginny, Harry's fringe keeps changing style between shots.
Continuity mistake: In Snape's flashback Harry's mother, as a child, has brown/black eyes. When she is an adult she has blue eyes.
Continuity mistake: Just after Harry and Lord Voldemort have their altercation in the Forbidden Forest, Neville is seen walking into Hogwarts' courtyard entrance to pick up the sorting hat. In the first shot, there is a camera angle of him from the waist down from behind, and he is stepping over the rubble and having no trouble walking. In the very next shot, you get a full frontal view of him walking, and he is limping and can barely move. (01:38:00)
Continuity mistake: When the students enter the Great Hall, Ginny is seen among them in full uniform. However, when one of the Patil sisters begins screaming, she can be seen in the casual clothing that she was wearing earlier in the Room of Requirement.
Continuity mistake: The pillow behind Griphook constantly moves between shots while the Trio is talking to him at Shell Cottage.
Continuity mistake: During the flashback to young Lily and Severus, while they are lying under a tree, their positions change, specifically the distance between them.
Continuity mistake: Throughout all the movies, the characters discuss several times how much Harry's eyes resemble his mother's. When we see flashbacks of Lily in this movie she has dark brown eyes. In past movies, when she was portrayed as a Hogwarts student, (in most of the same memories) she had blue eyes.
Continuity mistake: After Hermione destroys Helga Huffleluff's cup, the basilisk's skeleton vanishes during the Voldemort tsunami.
Continuity mistake: In the "limbo" scene at King's Cross when Harry is speaking to Dumbledore, Dumbledore's hair changes frequently. It is covering part of his beard, then is back behind his ear, then is hanging neatly down.
Continuity mistake: When the Snatchers run out of the forest toward the covered bridge, Neville is standing in the bridge's center. But when the three Snatchers are killed by the shield, Neville is now standing at the bridge's entrance. (00:50:50)
Continuity mistake: When Snape redirects Professor McGonagall's spell to Alecto Carrow, she falls on the lower platform. But after the camera angle changes, she is lying on the second platform with her brother Amycus.
Continuity mistake: During the epilogue, Hermione hugs her daughter Rose. In the first shot, Rose's left hand rests on her mother's back just below the shoulder. Cut to the following shot and the same hand is on Hermione's arm instead. (01:56:00)
Continuity mistake: During the final battle between Harry and Voldemort, Harry disarms Voldemort and his wand spins out of his hand counter-clockwise, then it cuts to the wand spinning towards Harry clockwise.
Continuity mistake: When Nagini (the snake) is moving down the stairs to attack Ron and Hermione, it lunges from midway down the stairs, under the archway. After intercutting a shot of the duel between Voldemort and Harry, Nagini is lunging from the ground, far away from the staircase and the archway.
Continuity mistake: During the duel between Harry and Voldemort whilst they are on the Hogwarts staircase, there's a midshot of Voldemort casting a spell. His arm is at an extreme bend with his elbow close to the top of his head, and his forearm is above his head. The very next shot from a different angle, Voldemort's arm is straighter and his elbow is not bent, with his arm a considerable length away from his head.
Continuity mistake: After arriving in Hogsmeade, when Harry is talking to Aberforth Dumbledore, the table by the window has two chairs on one side of the table. A few minutes later, there's only one chair on that side, and the other chair is now at the end where there was previously none at all. (00:28:00)
Continuity mistake: When Ron is about to cast a spell to destroy Nagini the view of him pointing his wand starts out from behind him and Hermione, before the shot changes we see Hermione turn her head towards Ron. When the shot changes to face them Hermione is looking at the snake then turns her head again.
