Mac OS X startup key combinations

Startup keyboard combinations have been around since the early days of the Mac operating system. Holding down specific keys while pushing the power button offer a plethora of options for troubleshooting when your Mac starts up.

Here are the most useful keyboard startup combinations:

Key/Combo What it does
⌥ (Option) Display all bootable volumes (Startup Manager)
⇧ (Shift) Perform Safe Boot (start up in Safe Mode)
C Start from a bootable disc (DVD, CD)
D Start up in Apple Hardware Test (AHT), if the Install DVD 1 is in the computer
T Start in FireWire target disk mode
N Start from NetBoot server
X Force Mac OS X startup (if non-Mac OS X startup volumes are present)
⌘-V Start in Verbose Mode
⌘-S Start in Single User Mode
⌘-⌥-P-R Reset NVRAM
Mouse button Eject CD/DVD and start up from hard drive

Most of these keyboard combinations will work with any modern Mac, but some models may have variations that work or don’t work.