Continuity mistake: At the end of the movie as Michael Clayton is hailing a taxi, there is a silver SUV and a moving truck behind the taxi. As he gets into the taxi, the SUV and truck disappear and there are only yellow taxis behind his own. (01:53:30)
Continuity mistake: When Stuntman Mike is eating and talking to the blonde girl in the bar, he is holding a glass of club soda. When the shot reverses, he is wiping his hands, then when the shot returns, he is holding the club soda again.
Factual error: At the very end of the movie, right before Javier Bardem is in the car accident, there is a shot out the driver's side window, past his face. In one of the driveways he is passing, a new Subaru Forester sits parked. The film is set in 1980.