Whenever an application hangs on the Mac (yeah, they do crash and burn at times), the next time you run the application you get a message about how the application "quit unexpectedly" (a nice euphemism). If you want to skip this message, there is a system setting that allows this. Open a terminal window and enter the following:

defaults write com.apple.CrashReporter DialogType none

and you will no longer get the message about applications that "quit unexpectedly". If you want to start getting the messages again, you can do so by entering this command on the terminal command line:

defaults write com.apple.CrashReporter DialogType prompt