If your Mac stops or delays while starting up
If your Mac freezes, displays a flashing question mark, or delays while starting up, you may need to select a different startup disk or repair your hard disk.
Note: To print these instructions, press Command-P.
If your Mac starts up after a brief delay or displays a question mark
You may need to select a startup disk.
Choose Apple menu
in the sidebar, then click Startup Disk on the right. (You may need to scroll down.)Select a disk, then click Restart.
Important: If you have a Mac with an Apple T2 Security Chip, added security features may need to be set in order to change the startup disk. See What is the Startup Security Utility? If you have a Mac with Apple silicon, see Change the security policy.
If you see a white screen with the Apple logo and a progress bar
If you see a white screen with the Apple logo and a progress bar, macOS is checking your hard disk. This check could take a few moments.
If you start up your Mac and the Apple logo doesn’t appear
Press and hold the power button for about 10 seconds to shut down your Mac.
Do one of the following:
On a Mac with Apple silicon: Press and hold the power button until “Loading startup options” appears, then select one of the disks.
On an Intel-based Mac: Press and hold the Option key, then press the power button to start up your Mac again. (Keep holding down the Option key until one or more disk icons appear on your screen.)
After your Mac starts up, choose Apple menu
Select a disk, then click Restart.
If your Mac doesn’t start up or there’s a delay while starting up
Disconnect all accessories, including USB, USB-C, and Thunderbolt devices.
Connect an Apple keyboard and mouse to your Mac. Do not use hubs or extension cords.
If you can use your Mac after connecting the keyboard and mouse, there may be a problem with one of the other devices.
Try reconnecting the other devices, one by one, to your Mac and restarting each time after you connect the device.
When you find the device that causes the problem, review its documentation for further troubleshooting steps.
If your Mac still doesn’t start up after you check connected accessories
Uninstall all third-party devices, such as PCI cards and ExpressCard/34 cards.
If you can use your Mac now, there may be a problem with one of the devices.
Try reinstalling the devices in your Mac, one by one, and restarting each time after you install a device.
When you find the upgrade that causes the problem, review its documentation for further troubleshooting steps, or contact the manufacturer.