Ways to start up your Mac
Normally you can restart your Mac by choosing Apple menu > Restart. However, in some cases—for example, if the pointer freezes on the screen or the Mac becomes unresponsive—you may have to use one of the startup methods listed here.
You can use these shortcuts when you start up your Mac. Unless otherwise stated, press and hold the specified keys immediately, while the screen is still black (some Mac computers play a startup sound).
Press and hold the power button on your Mac until it shuts off. After a moment, press the power button again to start your Mac. You may lose unsaved changes in open documents.
Prevent automatic login
When you see the progress indicator, press and hold the left Shift key.
Prevent login items and Finder windows from opening when you log in
After clicking the Log In button in the login window, press and hold the Shift key.
Start up from a CD or DVD
Start up from the default NetBoot disk image
Start up in target disk mode
Use Apple Diagnostics or Apple Hardware Test
Use macOS Recovery
See the Apple Support article About macOS Recovery.
Select a startup disk
To open the optical drive when choosing a startup disk, press Command-Period (.).
Eject removable discs
Press and hold the mouse or trackpad.
Press and hold the Media Eject key ⏏ or F12 key.
Reset parameter RAM
Show detailed status messages (verbose mode)
Start up in single user mode
Start up in Safe Mode (only essential macOS items are started; some features and apps might not work correctly)
Immediately after your Mac starts (some Mac computers play a startup sound), press and hold the Shift key. Release the Shift key when you see the progress indicator.