If you're using OS X 10.10 (or older), enter the command: sudo diskutil repairPermissions /.
If you're using OS X 10.11, enter the command: sudo /usr/libexec/repair_packages -repair -standard -pkgs /. (This is optional, though it's advised because it corrects file system issues that may persist.) Enter a command to repair your Mac's volume.( Note: No fonts will be deleted or removed.) Enter this command to simultaneously clear the Font Cache and remove the Font Database: sudo atsutil database -remove.In this mode, the font should look normal however, performance will be minimal. While in Safe Mode, the Mac will load only the basic OS files necessary to boot the system.Continue holding down the Shift key while the Mac boots to access Safe Mode. Power on your Mac holding down the Shift key.So how do you get your computer working properly again? With some well-placed Terminal commands, of course. Hiring kit: iOS developer (TechRepublic Premium).
