Character mistake: Kimble has just finished talking on the phone with his lawyer when the cops hear the noise in the background. They figure out the sound is that of an El-Train. They then start to list the different places that have an El. One of the cities they name is Milwaukee - there has never been an El-Train there.
Character mistake: At the end, when Mitch tells Agent Tarrance that the government can convict the law firm on mail fraud and racketeering, he says he got the idea while he was studying for the bar exam. He actually got the idea from a client earlier in the film when the client was complaining about being over-billed and tells Mitch that every time a bill is mailed through USPS, the firm is committing mail fraud which is a federal offense, punishable by fines and prison.
Suggested correction: This is not wholly correct. Mulholland (the client) planted the seed in Mitch's head, but Mitch realised instantly that it was a federal offense, presumably because he had studied it.
Character mistake: When Mrs. Doubtfire gets her own TV show at the end, she asks the puppet if he knows anything about England. The reply is, "I only know that it's an island", which is not true. Britain is an island, not England.
Character mistake: When Buster gets hit in the arm the first time, he is busy tying the kerchief below the wound. (02:21:05)
Character mistake: During the "heart attack prank" just before the paramedics get to Frank, Eastwood mistakenly opens his eye before the paramedics wake him.
Suggested correction: It's quite possible that Frank was awakened by the commotion of the EMTs rushing in.
Character mistake: Mike, despite being an experienced logger, is filing his chainsaw blade in the wrong direction. Also, he's seen filing the teeth of the blade way too many times.