Sometimes, errors can occur in Mail where the program will periodically hang, crash, or freeze, and will require a force-quit. Several things could cause this, including faulty preferences, corrupt mailboxes that need rebuilding, and errors in individual messages that result in odd behavior whenever the message is displayed. In addition to these possibilities, some shared resources that Mail uses could also contribute to crashes and hangs.
Preferences One of the first things to try when a program crashes or does not work properly is to remove its preferences. In this case, Mail's preferences are called "com.apple.Mail.… Read more