Continuity mistake: When Willy asks the decorator on the phone what's the difference between Italian and English, his Samsung Blade switches hands, switching back when he holds it against his chest. (00:33:05)
Character mistake: When Mr. Brooks and Marshall hack into the police database and are looking at detective Tracy Atwood's financial records there is a screenshot of the computer screen showing some very terrible spelling.
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)