A friend with a MacBook Pro (120gb, 10.4.11) keeps getting the message that his start up disk is full, even though he says he has 85gb of free space. What could be causing this, and what can be done about it? He says his log files (the only thing I could think of) only amount to a few megabites. And btw, he has no external hard disk. And yes, the trash is empty!