Startup Keyboard Shortcuts

Hold down the following keys to change the startup of an OS X Macintosh

Option - Choose the boot volume.

“C” - Boot from a CD or DVD

“N” - Boot from a network boot server

“T” - Start in Firewire target mode

Shift - Boot in “Safe mode”

Command-V - Boot in 'Verbose' mode

Command-S - Boot in Single user mode

Command-P-R - Zap the parameter RAM

Option-Command-Shift-Delete - Bypass the current default system disk and seek the next.

Notes

Firewire “Target” mode allows you to connect the Mac to another computer as an external Firewire drive and is used by the 'Migration Assistant” to move applications, users and settings from one Mac to another.

“Safe” mode turns off various extensions and facilities and may allow some Macs that crash during startup to proceed through to boot.

“Verbose” mode shows the boot process output on screen for the early part of the boot.

“Single User” mode boots to the Bash shell as root instead of launching the Login Window and Finder.

The “Bypass the current default startup disk” mode is useful when the computer refuses to recognise either Option or “C” on startup.