Most of the time, your Mac just works—until it refuses to start up properly due to an unforeseen system error, a misbehaving app, a broken system component and what not. Beyond system errors, different people have different needs when it comes to starting up their computer.
For example, you could be a pro user who dual boots between OS X and Windows on a daily basis. Others might be wondering about booting a Mac from a disk other than their designated startup disk. Or perhaps you’re looking to isolate the cause of a software issue in OS X’s Safe Mode or boot straight into Recovery OS as the last option?
For those of you who have wondered about the many ways you can start up your Mac, here’s a quick list of the keyboard shortcuts you can invoke to access handy OS X features which are only available at boot time.
Quick overview of Mac startup key combinations
To boot your Intel-based Mac into any of OS X’s built-in startup modes, you must press and hold one or more keys detailed below after turning on the computer. Press the keys immediately after hearing the startup sound, unless otherwise specified.
- 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 Inbutton 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.