
This shortcut ejects a CD or DVD from the optical drive. On a two- or three-button mouse, the primary key is usually the left button. Hold down the mouse's primary key during startup.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 Command (⌘) + "v" keys during startup to boot your Mac in Verbose Mode with a descriptive text sent to the display during the startup process.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 the Command (⌘) + Option + "r" keys during startup to cause your Mac to boot from the internet using Apple servers.


Hold the Option + "n" key to boot from the NetBoot default startup 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 "n" key during startup to boot from a networked computer that has a NetBoot volume.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 "c" key during startup to boot from a bootable CD, DVD, or USB flash drive.

In some cases, an alternate OS may prevent the Mac's normal boot manager from running. You may find this useful if you have your Mac set to boot to a non-Mac OS volume, such as Windows or Linux.
