Continuity mistake: When Kurt Russell and Michelle are having dinner in her restaurant, Michelle goes over to her counter to find an envelope with her name on it that is smeared from the rain leaking through the roof. Later she is shown opening that envelope and the writing is completely different, the name is positioned differently, and the name is smeared 3 times worse than before.
Character mistake: Mac's cousin says that even if Nick wasn't a cop, he'd have to hate Mac's guts. He says that Mac wears a Rolex and Nick wears a Timex - not true. Nick is wearing a Rolex, also.