For all of the below keys, hold them as you power the computer on.
https://support.apple.com/en-us/HT201255
Keys |
Action/Result |
Option |
Pick your startup device |
D |
Run Diagnostics on hardware from local machine |
Option-D |
Run Diagnostics on hardware, downloaded from internet |
Command-R |
System Restore |
Command-Option-R |
System Restore via Internet |
Command-Option-P-R |
Reset PRAM |
Command-S |
Terminal Window
Scan filesystem for issues (repeat several times):
fsck -fy |
Keywords: OS X, OSX, Apple, Macintosh, Powerbook, Powermac, IMAC, Macbook, Pro |