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.