Here are some goofs.
- Continuity: During the scene in which Harry consumes the Felix Felicis, he empties the entire vial into his mouth. However, in the following shot when he is holding the vial between his hands and is speaking to Hermione and Ron, the vial is completely full with the stopper still on.
- Revealing mistakes: Several times throughout the movie, Harry's glasses clearly have no lens in them. They are just the frames.
- Revealing mistakes: During the quidditch match, when Ron is celebrating a save, the wind blows his robes and you can clearly see the bicycle-like seat attached to his broom.
- Continuity: In the scene in the 3 Broomsticks pub, Slughorn spills some of his drink on the table and on Hermione. But a minute later when we see the table filmed from the side Slughorn was on, the table is dry.
- Continuity: In the last scenes of Dumbledore in the tower his beard was untied then a few seconds later was tied for the remainder of the scene.
- Revealing mistakes: Near the end of the film, when Harry is lying on the ground outside Hagrid's cabin, Snape kicks Harry's wand away from his hand. When he does so, a square of neon tape is clearly seen, almost right in the middle of the shot, where Harry's wand was placed, so that actor Alan Rickman would know where to kick.
- Continuity: In a scene where Harry goes to Dumbledore's office, Dumbledore is wearing glasses. When they go over to the cabinet where the mind serums are, Dumbledore's glasses are gone.
- Continuity: In the scene on the train where Lavender Brown is drawing on the glass, Harry pulls down the armrest of the chair. In the next shot, the armrest is up again.
- Revealing mistakes: When Professor McGonagall is examining the cursed necklace, she is standing in front of a window. During several of the shots you can see right through her.
- Continuity: When Draco unveils the vanishing cabinet in the Room of Requirement, there is a large amount of dust on the tapestries. When he goes back later in the movie the same amount of dust has gathered on the tapestries. The same amount of dust would not have accumulated in such a short amount of time.
- Revealing mistakes: When Harry is in bed looking at Malfoy on the Marauders map, it is obvious that his glasses contains no lenses.
- Continuity: During the first gathering at Hogwarts in the hall, the main entrance is closed while Dumbledore is speaking. When the camera changes, it is positioned outside in the corridor meaning the door opened somehow within seconds.
- Continuity: In the beginning of the movie, the waitress says that she gets off work at 11 o'clock, but soon after in professor Slughorn's home, all the clocks say 10:35.
- Incorrectly regarded as goofs: When Harry is petrified in the train, he's invisible under his cloak. But when Luna releases him, he gets up and there is no sign of the cloak. This is due to Luna's spell "finite," which undoes any spell cast on the target. This removes the Petrification spell cast by Draco earlier, and throws the invisibility cloak off of Harry.
- Continuity: The title says "Half-Blood", but the writing in the prop book says "Half Blood".
- Continuity: In the scene where Hagrid and Slughorn are drinking together, Hagrid's glass is markedly smaller than Slughorn's, a curiosity in its own right. Later, the glasses are shown next to each other and they are nearly the same size.
- Continuity: In the 3 Broomsticks, before Professor Slughorn spills his drink, from different angles it goes from having a foamy head to no head.
- Plot holes: In the book Draco Malfoy fixes the vanishing cabinet so that the Death Eaters can enter and launch a large attack on Hogwarts, however as this attack never takes place in the film (not counting destroying the Great Hall), it is questionable why he put himself through the effort of fixing it when he could have carried out all the actions himself.
- Continuity: When Harry first has the Half Blood Prince's potions book, his signature is in the front of the book. When Ginny takes it from him, she reads his signature from the back.
- Plot holes: When Loony Lovegood reveals Harry in the carriage, she uses a spell to remove his invisibility cloak, however, it is a Deathly Hallow, and as such is unaffected by spells. This is a vital point in the 7th book.
- Incorrectly regarded as goofs: The movie shows the destruction of the Millennium Bridge in London. The events in this part of the movie occurred mid-1996. The bridge's construction began late 1999. But while the books take place in the 1990s, no such time line has ever been given in the movies.
- Continuity: After Harry first arrives at the burrow, during the scene where he's talking with Ron and Hermione, Hermione's legs change positions from shot to shot.
- Continuity: When Harry and Slughorn go visit Hagrid, Hagrid sits with a wine bottle and an earthenware goblet and Slughorn has only a goblet on his side of the table. At the end of the visit, Slughorn's goblet magically appears right next to Hagrid's goblet on his side of the table.
- Revealing mistakes: The scene in Hagrid's Hut while Harry and Slughorn are talking. Harry talks about his scar and points to his forehead, but there is no scar visible.
- Continuity: It has been established in other films that the Weasley home is surrounded by trees. In this movie it is located in the middle of a huge empty field.
- Anachronisms: The potions book which Harry gets from Slughorn's cupboard has the words "This book is property of the Half-Blood Prince" clearly handwritten on the first page. In a later shot the handwriting changes to a more print-like font.
- Continuity: Throughout the film, Dumbledore's "burnt" hand clearly switches from his right hand to his left. When Harry and Dumbledore apparate together the first time from the train station, Dumbledore motions with his right hand, and we see it's burnt. However, when the pair are going into the cave, and they have to make a Blood Offering, Dumbledore cuts his left hand, which is now the burnt one.
- Continuity: When Harry is staying at the Burow it is Christmas, but outside it clearly looks like summer and the corn is the field is high.
- Crew or equipment visible: In the scene where Harry and Dumbledore are setting out together from Hogwart's, a crew member's feet are clearly visible and moving around behind one of the sets. The crew member promptly tries to get out of the shot.
- Crew or equipment visible: At the beginning when Harry and Dumbledore first disapparate, there is a full shot of them walking up to the entrance of the house. In this full shot, you can see Dumbledore's shoes sticking out of his robe as he walks, only he is actually wearing those blue bags on his shoes, the ones they wear in between takes so as not to damage the set floors.
- Revealing mistakes: When Harry and Dumbledore are in Voldemort's cave and pulling up the boat you can see that Dumbledore is wearing a black glove on his 'injured' hand.
- Errors made by characters (possibly deliberate errors by the filmmakers):
Professor Slughorn calls Harry's Draught of Living Death perfect, and remarks that it could kill everyone. But the Draught of Living Death is a sleeping potion, not a poison. - Incorrectly regarded as goofs: Katie Bell is seen in Harry and Ron's potion class, despite being in the year above them. This was changed for the movie to simplify the story.
- Continuity: During the Felix Felicis scene, when Slughorn gives it to Harry, he is holding it with his hand below the bottle. In the next clip, his hand is above it.
- Continuity: In the scene where Katie Bell is reacting to touching the necklace, her fingers are exposed while she's on the ground, but once she goes up in the air they appear covered up.
- Plot holes: Dumbledore and Harry apparate from Hogwarts to the rock cave, and apparate back. No one can apparate into or out of Hogwarts (according to the books). The only way the Death Eaters could enter Hogwarts was by way of the Vanishing Cabinet. If they could have apparated onto the school grounds, they would have.
- Revealing mistakes: During the scene in Professor Sluhorn's lesson, the students are told to make a Draught of Living Death, the recipe for which "can be found on page 10". During the lesson, it is quite clear that Hermione has her book open somewhere in the middle (circa page 200).
- Incorrectly regarded as goofs: According to the last movie, you need to know the purpose of the Room of Requirement to be able to access it. Harry and Ginny were looking for a place to hide the book, so the Room allowed them access.
- Incorrectly regarded as goofs: During the scene when Dumbledore first introduces Harry to Professor Slughorn, Slughorn's robe changes color more than once. However, this is due to the florescent lighting outside of Slughorn's home.
- Audio/visual unsynchronized: After checking his breath in the coffee shop the sound of mints rattling can be heard as Harry pulls them out of his pocket, however when the mints are shown they are in a roll, which would not make a sound as implied.
- Incorrectly regarded as goofs: Dumbledore has Riddle's diary in his possession. The last time it was shown was in the the second movie, and Lucious Malfoy was the last person to have the diary. Lucious then gave the book to Dobby with Harry's sock hidden inside to set him free, Dobby was still holding it when he stopped Lucious from cursing Harry. The book was left on the floor, meaning either Harry or Dumbledore could return the book to the headmaster's office.
- Incorrectly regarded as goofs: At the end of the movie when everyone is holding their wands skyward in tribute, Hagrid can be seen holding a wand. In the first movie, he had hidden his first (broken) wand in a pink umbrella, but after his name was cleared in the second movie, he was able to get a replacement wand.
- Incorrectly regarded as goofs: SPOILER: When Snape casts Avada Kevada, the light emitted is blue and white, when previously it has always been green (in both books and movies). However, this is possibly correct because it is learned in the last book that Snape did not kill Dumbledore in malice, but in mercy. The change in color was probably an intentional clue added by production to indicate this difference.
