How To Boot Your Mac In Safe Mode
Starting up in Safe Mode also does a directory check of the startup disk, disables non-system fonts, turns off hardware accelerated graphics, stops file sharing, and clears cache files that could be the root of your problems. To start up in safe mode, Shut down the computer completely. Press the power button to turn the computer on and hold the Shift key immediately after the startup chime is heard. This must be done quickly....