The Harry Potter film series captivated the world for about a decade, yet it wasn’t without faults. The movies were made with some major limiting factors, and plenty of gaffes slipped through into the finished product. Below are seven of the biggest mistakes that you can still see in rewatches to this day — but once you know they’re there, you may never be able to look at Hogwarts the same again.
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The Harry Potter movies were made at a time when special effects technology and attitudes were changing rapidly, which is a big factor in some of the mistakes you’ll see below. They also necessarily starred a large cast of child actors, whose inexperience definitely contributed to some of the bloopers and mistakes in the movies. On top of that, the largely British cast had different protections than we normally see in American productions, as they have discussed many times in behind-the-scenes featurettes.
All that added up to plenty of memorable flubs in the seven years we all spent together at Hogwarts. Read in for seven of the most unforgettable gaffes of the series.
“Invisibility” Cloak
Harry’s invisibility cloak is a relatively simple visual effect to pull off — it’s made out of green screen material, and altered in post-production. However, in one shot of Harry Potter and the Sorcerer’s Stone, they forgot to change its appearance, leaving the crumpled green cloak you can see above, just behind Harry’s foot. For those interested, this is the scene where Harry takes Ron to see the Mirror of Erised, about 1 hour and 30 minutes into the movie.
Cameraman
The dueling club scene in Chamber of Secrets is not only full of action, it’s an exciting character moment as Harry faces down Malfoy. With all that going on, you could be forgiven for missing the shot above where a cameraman is clearly visible in the left side of the shot, nestled in among the students.
Crystal Ball
About an hour and 20 minutes into Harry Potter and the Prisoner of Azkaban, Hermione has finally had enough of divination class. She knocks over a crystal ball and storms out, but if you pause you’ll notice that it’s not perfectly spherical. There’s a small red and black tube sticking out of the bottom — perhaps meant to hold it steady, or perhaps to aid in the light and smoke effects within. Either way, it’s gone a few shots later when Harry picks up the ball off the floor.
[RELATED: Harry Potter Fans Still Upset Over That Voldemort Scene: “Worst Change They Ever Made”]
Ruled Parchment
It doesn’t always make sense that modern wizards use outdated technology like quills and ink instead of pens and pencils, and the movies seem generally less interested in this than the books were. By Harry Potter and the Goblet of Fire, we’re used to seeing the students out of uniform most of the time, but the school supplies still seem mostly dated. The exception is oddly prominent — when Harry’s name comes out of the Goblet of Fire, it’s written on a piece of blue-lined notebook paper. The other three champions’ names are on parchment, and this is especially odd when you consider that it was actually Barty Crouch Jr. disguised as Mad-Eye Moody who put this name in the goblet.
I Must Not Tell Lies
Professor Umbridge forces Harry to scar his left hand with the phrase “I must not tell lies” in Harry Potter and the Order of the Phoenix, but the scar actually changes hands several times throughout this movie. It seems easy enough to remember since Harry has to write the phrase with his dominant hand, but perhaps the filmmaker wanted to switch hands now and then to make sure the scar was prominent when it needed to be.
Millennium Bridge
The opening scene of Harry Potter and the Half-Blood Prince has one of the most infamous anachronisms in the whole series. It shows the Death Eaters attacking the Millennium Bridge in London, but that bridge shouldn’t even exist yet in the movie’s timeline. This part of the story takes place in 1996, while the Millennium Bridge wasn’t opened until 2000. There are plenty of other anachronisms, but this one is the most prominent.
An Awkward Kiss
Finally, Ron and Hermione’s first kiss at the climax of Harry Potter and the Deathly Hallows Part 2 simply didn’t do it for some fans, and we know why. In the Harry Potter 20th Anniversary: Return to Hogwarts special, Emma Watson and Rupert Grint explained how difficult it was for them to commit to this kiss because they had grown up together, and regarded each other like siblings. Daniel Radcliffe even added that he teased them mercilessly about it, making it even harder for them. For some fans, all that tension came through in the finished product — and not in a good way.
All eight Harry Potter movies are streaming now on Max, along with the Fantastic Beasts movies. A new adaptation of Harry Potter as a TV series is expected to debut in 2026 on HBO and Max.