I have a 2009 Mac Pro ("Cyrus"). Connected to it are via USB and video an Apple Cinema Display. Connected to the Cinema Display are an apple keyboard and to it an Apple Mighty Mouse. Sometimes the mouse pointer freezes (or rather is found frozen when I return to the machine and the screen saver was on) and the only way to get it back to work is to disconnect the mouse and reconnect it. However, every second or so time I do this, the Mac Pro crashes. The screen turns darker and in the middle a multilingual text tells me that I have to restart my Mac. Does this happen to anybody else? How can I prevent it and why does Mac OS X crash over a USB event?