Revealing mistake: When Tim Allen startles Santa Clause and he falls off of the roof, Santa's foot kicks up a blanket that was used to look like some snow on the roof. (00:14:10)
Continuity mistake: In court, the camera shows Susan to judge her reaction to the lawyer talking, and she is sitting upright in her seat. It then changes to Dori, who is sitting right next to Susan. If you look in the bottom left hand corner however, you'll see that Susan is no longer sitting upright, and is instead leaning on Dori. There would be no time however for Susan to lean on her mother in the time the camera takes to move to another shot.
Continuity mistake: While Bill waits for his brothers in the car, he looks toward the store and watches his brothers inside. The first shot of Bill's perspective of looking at the store, there is a reggae black man walking by. Then it switches back to Bill's face, then again at the store and the man walks by the window a second time in the same direction. When Bill gets out of the car and crosses the street the black man walks by a third time.