Mac Startup Keys

Manually restart: Power (⎋)

Boot from CD/DVD: C

Startup Manager: Option (⌥)

Single-User Mode: Command (⌘)—S

Target Disk Mode: T

Verbose Mode: Command (⌘)—V

Safe Mode: Shift (⇧)

Recovery OS: Command (⌘)—R

Internet Recovery OS: Command (⌘)—Option (⌥)—R

Apple Hardware Test: D

Apple Hardware Test over the Internet: Option (⌥)—D

Boot from NetBoot server: N

Boot from NetBoot server using the default image: Option (⌥)—N

Eject removable media: Media Eject (⏏), F12, mouse button or trackpad button

OS X Startup Volume: X will start up your Mac from an OS X startup volume when it’d otherwise boot from a non-OS X volume, like a Windows partition

Prevent Login Items from opening: To override your current settings and prevent Login Items and Finder windows from your last session from opening when you log in, hold down the Shift (⇧) key after clicking the Log In button in OS X’s login window until the desktop appears.

Prevent automatic login: If you enabled the option to automatically log a specific OS X account every time your Mac starts up, you can override this setting by holding the left Shift (⇧) key after OS X’s boot progress indicator appears.

Reset PRAM/NVRAM: Command (⌘)—Option (⌥)—P—R, then release the keys after you hear the startup sound for a second time

Reset SMC: Shut down your Mac, and then press and hold the left-side Shift (⇧)—Control (⌃)—Option keys along with the Power (⎋) button, all at the same time, until the computer turns on. Now release the keys and then turn your Mac back on using the power button.