When the guys are in the library looking at the scans, the name of the cemetery of the child's burial is different from the name that is announced out loud. Additionally, if you look closely, the text constantly repeats itself on the page.
Though out the movie Linda's fingernail polish changes from red to clear
The POV shots of Linda's hands are different from the side-angle when she's possessed by Malfaitor.
When James is laying unconscious on the dock, he has his legs together in all shots, except in the last closeup shot where he is laying with his legs apart.
When Linda is using the Ouija board and tells David that she's giving the board back, in one shot her bare legs are shown as she holds the board on her lap. In the next shot, she has one leg crossed under her and the robe is covering her legs.
When Linda is attacked in the shower by the water turning hot, she breaks through the glass to escape. The sound effect for the shower is still going but you can clearly see the shower is now turned off.
You can see where the lines on the ropes holding the barrels are marked to break.
After Linda found her diamond ring in the bathroom sink drain, James shows up and startles her. At one point, you can see James in the mirror with his mouth moving but his voice couldn't be heard.
The cameraman's shadow visible during a close-up of the hatchet hammer lying on the sheetrock.
When Zarabeth is being chased up stairs by the as yet unidentified spirit, you can see the shadow of a cameraman and a mic boom.
Boom mike visible at the top of the screen after Zarabeth asks David to turn on the lights.
In the third act when the "spirit" cam cranes up to the second floor bedroom and into the window, you can see the set lights reflected in the window, the bedroom mirror and the bathroom mirror.
When Lt. Dewhurst is talking to Jim and Linda after Lloyd's funeral, he incorrectly refers to the late, legendary Las Vegas magicians as Sigmund and Roy and not Siegfried & Roy.