All the Special Keyboard Shortcuts That Change Your Mac’s Startup
The startup sound is the Mac’s way of letting you know that everything is fine, but sometimes things don’t go well and you need to boot in a different mode than usual. Macs have a variety of options to do this, and all they need to do is hold down the keyboard shortcut while booting.
To boot into one of these modes, press and hold these keyboard shortcuts immediately after turning on your Mac. Hold them down until your Mac boots into the mode you want. Here are the keyboard shortcuts and what you would use them for:
- Shift : Starts your Mac in Safe Mode . This helps troubleshoot problems because boot only loads the minimum required kernel extensions and then disables startup items, user-installed fonts, font caches, kernel caches, and other system cache files. Safe mode also automatically performs a file system check to help troubleshoot problems.
- Option : This loads the startup manager, in which you can choose between different hard drives or drives to boot. If you need to boot from a hard drive other than your main drive, or you boot into Boot Camp, you press this key.
- C : Boot from bootable CD, DVD, or USB. This is useful when installing a new operating system.
- D or Option + D : Run the Apple Hardware Test on Macs prior to 2013, or the Apple Diagnostics Utility on newer Macs. Both are for hardware troubleshooting.
- N or Option + N : Started from a network boot server . Most casual users will never need this as it is designed to run OS X offline and not on a hard drive or floppy drive.
- Command + R : Starts in recovery mode . If you’re having problems with your hard drive, OS X Recovery lets you restore your Mac from a backup, check and repair your drive, check your internet connection, or reinstall OS X.
- Command + Option + R : Launches the online version of recovery mode, which works the same as normal recovery mode, but is online.
- Command + Option + P + R : Resets NVRAM. NVRAM stores information about speaker volume, screen resolution, boot disk selection, and recent kernel panic information. If you are having audio or video problems, it is usually a good idea to reboot the NVRAM before you panic.
- Command + S : Runs in single user mode . This is mainly aimed at developers and IT pros as a startup troubleshooter and basically lets you go to the command line where you can run tests without worrying about the GUI on OS X.
- Command + V : Runs in verbose mode . Verbose mode is similar to single-user mode, but is more for monitoring the computer’s actions for troubleshooting.
- T : Starts your Mac in target disk mode . It’s a useful way to share files between two Macs when one is broken or the display isn’t working.
- Eject button, F12, mouse button, or touchpad button : Force ejects the optical disc.