If your Mac doesn’t start up as expected
If your Intel-based Mac computer displays a blank or blue startup screen, or a question mark on the startup screen, there may be a problem with firmware updates, startup items, or software.
Tip: If an Apple Support URL is shown on the startup screen, you can enter the URL on another device to access information about the issue and suggestions to resolve it.
Blank startup screen
If your Intel-based Mac computer displays a blank screen at startup—or a screen with an Apple logo (with or without a gear icon) and a flashing question mark—it indicates there may be a problem with a firmware update or software. Try these suggestions.
If you just installed a new version of macOS, make sure your Mac has the recommended memory and disk space. To check, choose Apple menu > About This Mac, then click More Info. If your Mac doesn’t meet these specifications, reinstall your previous version of the operating system.
Blue startup screen
If your Intel-based Mac computer displays a blank blue screen or a blue screen with a multicolor pinwheel at startup, it indicates there may be incompatible startup items or software. Try these suggestions.
Restart your Mac in safe mode. If your Mac successfully starts up in safe mode, choose Apple menu > Restart to restart your Mac normally.
Check your login items to learn if any of them are incompatible.
Use the Disk Utility app on your Mac to repair your startup disk.
Back up your disk, then reinstall macOS.
Use macOS Recovery, part of the built-in recovery system of your Mac. See Use macOS Recovery on an Intel-based Mac.
Question mark on the startup screen
If your Intel-based Mac computer displays a flashing question mark at startup, it indicates your Mac may not be able to locate system software. Try these suggestions.