I have a problem here I can't seem to fix. Hope for some help. I have 2012 13" rMBP. Out of 500GB, there is only about 300MB of free space. Every application crashes including Finder, so I can't even delete anything except the stuff on the Desktop. The drive is encrypted with FileVault, but I can't decrypt it because System Preferences crashes as well. I have been able to backup important files, so I figured I'd just wipe the drive, but there is another problem. The owner (my mom) no longer remembers her Firmware Password, so I can't even change start up volumes or select Internet Recovery. I have been able to backup and then free some 15GB of space. The computer is on Mountain Lion. The only recourse I see is hopefully by upgrading to Mavericks it will reinstall some of the system apps like Finder to factory and therefore fix the issues we have caused by the full disk. That is, unless someone has better advice? I'm all ears.