Revealing mistake: During Quidditch tryouts, when Ron blocks the Quaffle with his head in the closeup, Ron's body disappears at the bottom of the screen below the digital editing line. (Only visible on fullscreen DVD).
Revealing mistake: When John is stuck in traffic and he walks up to the other man asking if anyone was hurt, the guy looks behind John's shoulder as if the plane is coming right behind him. Then John turns around and looks right behind him as well. But the camera then pans all the way to the side to see the plane coming in before it crashes - they were looking in the wrong place.
Revealing mistake: When Langdon and Victoria walk towards the Pantheon, the first two angles show them walking alone with some stunt-women behind. But in the third angle, a couple of seconds later, a huge line of people appears, lining perfectly in the back, watching the camera. Obviously a group of real tourists standing behind a security line watching the shooting.
Revealing mistake: When Holmes is being chased through the boatyard by the giant, he trips over the ship's mooring chain. The links are over a foot long, and should weigh 100 pounds each, yet the whole chain jiggles like it's made of Styrofoam.
Revealing mistake: When William is running at the end, there is already a blood trail on the floor. Clearly from another take. (01:15:10)
Revealing mistake: During crash scenes towards the end the local traffic in the background is driving on the left hand side of the road (filmed at Darling Point, Wynnum, Australia) even though the movie is set in the USA.
Revealing mistake: When both Lisbeth and Mikael open their Apple Mac computers and use them, the little apples on the outside should light up, but they don't - neither computer does; they're switched off or not powered up - Mikael even goes to the trouble of connecting his to a power cord.
Revealing mistake: During the fight scene at the rest area, Gina is hitting Dick, and her sweater rides up her back, revealing the battery pack for the microphone taped to the small of her back.
Revealing mistake: In the scenes where Sam 1 and Sam 2 are in touch, the double is completely wrong. Wrong hair, wrong profile and wrong hind end.
Revealing mistake: When the soldier is tempering, you can see sparks fly before the hammer hits the metal.
Revealing mistake: When we see Clouseau hanging on the chandelier on the CCTV at Alonso's mansion, you can see it is not Steve Martin but his stunt double.