Factual error: A carton of HEB milk is taken out of the fridge and it has the new (as of 1994) label on it. The movie is set in the late 80s, when the old style label was still used.
Factual error: "A Friend's" emails from the Univ. Of Washington look ridiculous with just text and an abbreviated name on a colored background. UW emails have a white background, the addresses have a "uw.edu" domain name and show staff name, credentials, title, and department. The UW name, logo, and other info are included. Prof. Friend's student assistant (son of Tom's co-worker) sent the emails from Friend's office, but he could have sent anonymous ones using a public WiFi and with Yahoo, Hotmail, or Google email.
Factual error: Macaulay Culkin hides the gold coins in the duffel bag of a mall mannequin, Problem is, gold is heavy. It would rip the plastic arm, the duffel bag, or yank the mannequin over (and assumes store people won't change it anyway).
Factual error: When Mr. Sutphin finds Beverly's things on Richard Speck, there's an envelope he mailed her, with his return address, which is wrong. It is listed as Stateville Correctional Center (which is where Speck served his time in real life): Joliet, Illinois 60434. However, SCC is located in Crest Hill, Illinois 60403.
Factual error: In the beginning of the movie, Dr. Bob Moore falls through the glass doors of his office and is impaled with the glass. This would never have happened. It is federal law that safety glass is used in all entry doors. The glass would have to have been made of tempered glass, which breaks into tiny pieces like a car window, or laminated glass which will crack and bend but stay intact like a car windshield, or of wire glass, which will act similar to laminated glass. None of these was used. A plain standard plate glass was used instead.
Factual error: In one scene Cobb and the sportswriter doing his biography are driving across the country to get to the baseball Hall of Fame. They are stopped next to some railroad tracks fixing a flat tire, and a train goes by that has Burlington Northern markings (BN). Burlington Northern didn't come into existance until ten years or so after Mr. Cobb died.