Errors in geography: The film is set in L.A. At the end of the movie, the sun is shown rising over the ocean (some have argued that the time is uncertain and that it could just as easily be sunset).
Continuity: Price's name appears on the poster and the bankdrafts as Steven Price, however, in the closing credits, Geoffrey Rush is credited as Stephen Price.
Continuity: Pritchett empties the remaining scotch from the bottle into his glass twice before Eddie knocks the glass out of his hand.
Revealing mistakes: When the camera tracks in on Schecter in the control room in the haunted house, there are two very conspicuously CG-added Blockbuster video boxes under some paper. They wobble as the camera moves closer to them.
Continuity: The scar on Evelyn's face keeps changing sizes and positions on her right cheek.
Continuity: The scars on Sara's forehead and cheek keep vanishing and reappearing on different sides of her face, and are all completely gone by the end of the film.
Continuity: In the final chase, Sara's jacket disappears between shots (shots where she loses the jacket were cut).
Revealing mistakes: Some of the warnings in the basement are in very bad German - it seems somebody just used a dictionary and translated the English lines word-for-word. For example, one sign has the phrase "Steh zurück!" which means something like "Stay back!". A correct translation would be "Zurückbleiben" or in this context "Eintritt verboten" ("No admittance").
Continuity: When Price takes them all to the casket to get the guns, one of the windows is not shuttered yet "lockdown" had already happened.
Audio/visual unsynchronized: When Melissa Margaret Marr first screams, she screams when she sees the ghost. When everyone looks over her tape, she screams when the ghost takes her into the house.
Continuity: Sara Wolfe's wandering through the basement is out of sequence. At one part she wanders into a darkened room filled with debris, but then in the close-up, there is a light through a door to her right as well as a clear path for her. In fact, the halls she wanders through keep changing from long shot to close-ups.
Boom mic visible: When Taye Diggs and Ali Larter walk into the Zoetrope room, the mic is visible at the top right of the screen, peeking out from behind the zoetrope tank. Diggs' flashlight shines right on it at one point.
Continuity: At the beginning Sara introduces herself as Jennifer Jensen, but later on when she is looking for Melissa Marr just before shooting Price she is calling out to her saying, "It's Sara." But she only revealed that she is Sara while talking to herself.
Continuity: After the electroshock machine is turned off, the hood on Evelyn's head is unbuckled twice, first by Mr. Price then by Dr. Blackburn.
Revealing mistakes: Near the beginning, after Mr Price has 'sent' his copy of Evelyn's Guest List by memo, there's the shadow of a crew or camera member over the laptop when the 'house' starts making the changes to the guest list.
Continuity: When Pritchett, Sara and Eddie are first in the basement, and Sara give the torch to Pritchett. You see him raise his hands in the air, and neither of them shows any evidence of the cuts he sustained while breaking the glass in an earlier scene.
Continuity: When Sara and Eddie are in the lobby en route to the attic (which is at the top of the tower, proven by the fact that when they escape out the window, that is where they end up), "the house" is right behind them. It is not plausible for them to be able to run all the way to the attic without being engulfed by the house.
Errors made by characters (possibly deliberate errors by the filmmakers): In the scene where Price, Baker, Sara, and Pritchett are first exploring the basement, Pritchett says that nothing has been done to the basement area of the house since 1931. However, throughout the movie we can clearly see halogen lights mounted on the walls throughout the rooms in the basement.
Revealing mistakes: Several times during the movie, a character cocks a gun and the click of a gun being cocked is heard, but each time, the gun the actor is holding is shown with the hammer in the decocked position.
Anachronisms: The movie is set in 1931 and shows a room for electroshock therapy. That therapy will be invented only in 1938 (Cerletti and Bini).