Startup Keyboard Shortcuts
With startup keyboard shortcuts, you change the default behavior of your Mac when it starts up. You can enter special modes, such as Safe mode or Single-User mode, both of which are troubleshooting environments, or you can use startup shortcuts to select a boot device other than the default startup drive you usually use. The many startup shortcuts are gathered here.
Using a Wired Keyboard
When you use a wired keyboard, enter the keyboard shortcut combinations immediately after pressing the Mac’s power switch. When you use the Restart command, use them after the Mac’s power light goes out or the display goes black. If you’re having problems with your Mac and are using the startup keyboard shortcuts to assist in troubleshooting, use a wired keyboard to eliminate any Bluetooth problems that may prevent the Mac from recognizing the use of keyboard shortcuts. Any USB keyboard works in this role; it doesn’t need to be an Apple keyboard. If you’re using a Windows keyboard, learn about Window’s keyboard equivalents for the Mac’s special keys to figure out the proper keys to use.
Using a Wireless Keyboard
If you’re using a wireless keyboard, wait until you hear the startup sound and then immediately use the keyboard shortcut. If you hold down a key on your wireless keyboard before you hear the startup chimes, your Mac won’t correctly register the key and will likely boot up normally. Some Mac models from late 2016 and later lack the startup chimes. If you’re using one of these Mac models, press the appropriate startup key combination immediately after starting your Mac or immediately after the screen goes black during a reset. These startup shortcuts come in handy when you need to troubleshoot your Mac, or you want to boot from a different volume than usual.
Startup Shortcuts
Hold the “x” key during startup to force the Mac to boot from OS X or macOS, no matter which disk is specified as the startup disk. You may find this useful if you have your Mac set to boot to a non-Mac OS volume, such as Windows or Linux. In some cases, an alternate OS may prevent the Mac’s normal boot manager from running. Hold the “c” key during startup to boot from a bootable CD, DVD, or USB flash drive. If you have created a bootable Mac OS installer on a flash drive, this is an easy way to boot from the installer. Hold the “n” key during startup to boot from a networked computer that has a NetBoot volume. NetBoot volumes can be created with OS X or macOS Server, allowing you to boot from, install the Mac OS, or restore the Mac OS from the server on your local network. Hold the Option + “n” key to boot from the NetBoot default startup volume. Hold the “t” key during startup to boot in Target Disk Mode. This mode lets you use any Mac with a FireWire or Thunderbolt port as the source for your boot-up system. Hold the “d” key during startup to boot up using the Apple Hardware Test (AHT) or Apple Diagnostics. Hold the Option + “d” key during startup to boot up using the AHT over the internet or Apple Diagnostics over the internet. Hold the Option key during startup to open the Mac OS startup manager, allowing you to select a disk to boot from. The startup manager searches all the volumes connected to your Mac and displays those that have a bootable operating system. Hold the Shift key during startup to boot your computer in Safe Mode. Safe Mode disables login items and nonessential kernel extensions. Hold the Command (⌘) + “r” keys during startup to cause your Mac to use the Recovery HD partition, which allows you to restore the Mac OS, or use various utilities to troubleshoot your Mac. Hold the Command (⌘) + Option + “r” keys during startup to cause your Mac to boot from the internet using Apple servers. A specialized version of the Mac OS runs that includes a small suite of utilities, including Disk Utility, and the ability to download and install the Mac OS or to restore from a Time Machine backup. Hold Command (⌘) + “v” keys during startup to boot your Mac in Verbose Mode with a descriptive text sent to the display during the startup process. Hold Command (⌘) + “s” during startup to boot your Mac in Single-User Mode, a special mode used for troubleshooting and repairing complex hard drive issues. Hold down the mouse’s primary key during startup. On a two- or three-button mouse, the primary key is usually the left button. This shortcut ejects a CD or DVD from the optical drive. Hold Command (⌘) + Option + “p” + “r” during startup to zap the Parameter RAM (PRAM), an option that long-time Mac users will remember. Press and hold the key combination until you hear the second set of chimes. Zapping the PRAM returns it to its default configuration for display and video settings, time and date settings, speaker volume, and DVD region settings.
