Information Technology Reference
Perform a Safe Boot
Apple provides a special way to boot into Mac OS X called Safe Mode
(entering that mode is called performing a Safe Boot ). A Safe Boot
temporarily disables most low-level third-party software (as well
as several Apple products). It also disables any login items (programs
or documents listed in the Login Items view of the Users & Groups
system preference pane), which normally open when you log in. Safe
Mode also clears certain caches that would otherwise load at startup
and performs some additional checks and maintenance.
To perform a Safe Boot, follow these steps:
1. Turn off your computer. (Seriously: don't just restart. Choose
Shut Down from the Apple Menu or press the power button,
and click Shut Down in the dialog that appears.)
2. Press the power key to turn your computer back on.
3. As soon as you hear the startup chime, press the Shift key and
hold it down until the gray Apple logo appears in the center of
Your Mac will complete the startup process, which may take
considerably longer than usual. You'll eventually see the words
“Safe Boot” on the screen. When you're finished running any tests
you have to do in Safe Mode, you can reboot normally.