Corrected entry: In the chapter 'The Rogue Bludger', Harry breaks his arm in the quidditch match against Slytherin and Madam Pomfrey said "This boy needs rest, he's got thirty-three bones to regrow!" There are only 30 bones in an arm.
Corrected entry: The Hogwarts' school supply list mentions the Lockhart book, "Wanderings With Werewolves," but later, Lockhart refers to the book as, "Weekend With a Werewolf." (May be corrected in later editions of the book).
Corrected entry: Hermione says Moaning Myrtle haunts the bathroom on the first floor. However, when Harry sees the writing on the wall outside her bathroom, he is on the second floor.
Corrected entry: When Harry enters Tom Riddle's memory of catching the "Heir of Slytherin," he is in the headmaster's chamber. but Tom isn't in the room yet. He enters shortly, but how can Harry see Dippet if Tom wasn't there to remember it?
Corrected entry: Ron and Harry both fly the Ford Car straight into Hogwarts Grounds. However, Dumbledore has strict spells bound onto the Castle border that prevent anything from flying over the castle walls.
Corrected entry: Ron said that Fred turned his teddy into a spider when he was 3 years old. But Fred would have been 6 or 7 at the time and wizards don't get their wands until they are 11.
Corrected entry: In this book Percy takes 10 points from Gryffindor, when Ron Harry and Hermione are outside the girls bathroom on the second floor. "Ten points from Gryffindor" said Percy, fingering his prefect badge. However, later in the series, once Umbridge begins teaching, Malfoy tries to dock points from Harry, Hermione and Ron, and Hermione says "Prefects can't take points from students, Malfoy, only teachers can".
Corrected entry: Hermione has mentioned several times (but this may be in later books) that nobody can Apparate or Disapparate to/from the Hogwarts grounds, but Dobby frequently does this. It may be that the rule only applies to humans, but surely a clever wizard like Dumbledore would make sure that the Apparating/Disapparating rule applies to all creatures and not just humans.
Corrected entry: During the Flourish and Blotts scene, Harry is presented with a complete set of his needed books by Lockhart. He then dumps these into Ginny's cauldron, mumbling 'I'll buy my own'. But before he is able to, the fight breaks out and they then immediately leave the store, travelling home by Floo powder without re-entering the store. Where did Harry get his books from, then?
Corrected entry: On page 182 (page may be different for different versions), Harry is still in the hospital, yet when he wakes up, it says the dormitory was blazing with winter sunlight.
Corrected entry: On page 105, Harry finds Mrs Norris petrified on the second floor. When Dumbledore asks them all to follow him, Lockhart tells Dumbledore to use his office, and he says that it's just upstairs, which would mean Lockhart's office is on the third floor. But on pages 91-92 it says that Harry is dragging his feet along the second-floor corridor to Lockhart's office for his detention.Issabee
Corrected entry: Hermione says the lacewings for the Polyjuice Potion have to be stewed for 21 days. But on page 184 Ron pours the dead lacewings on top of the leeches. They couldn't already add the lacewings, as it is only the first day.
Corrected entry: The picture at the beginning of "The Rogue Bludger" shows Harry's left arm deboned. However, it says his right arm was the one that got deboned.
Corrected entry: It states in the book that ghosts can't eat or drink, so how is the Mandrake Potion administered to Nearly Headless Nick?