These instructions apply only to Mac computers with an Intel processor.
Erasing your Mac permanently deletes all of its files, so make sure that you make a backup of any files that you want to keep. If you're attempting to restore your Mac to factory settings, first learn what to do before you sell, give away, or trade in your Mac.
Start up from macOS Recovery
Turn on your Mac, then immediately press and hold these two keys until you see an Apple logo or other image: Command (⌘) and R. You may then be asked to select a user you know the password for. Select the user, then click Next and enter their administrator password.
I tried to start up my computer and got a flashing file with a question mark. So I held down the ⌥-key on boot and brought it into recovery-mode. After going through the different options I went to the disk utility and all I see is the grayed out SuperDrive and below there is disk0 and Mac OS X Base system. Tucked away in the Utilities folder, Disk Utility and its First Aid feature can be used to check if a disk is damaged and repair it, create a disk image, partition a disk, and so much more. Use Startup Security Utility to make sure that your Mac always starts up from your designated startup disk, and always from a legitimate, trusted operating system. If you're using a Mac with the Apple T2 Security Chip, Startup Security Utility offers three features to help secure your Mac against unauthorized access: Firmware password.
Use Disk Utility to erase your disk
Disk Utility Macbook Air
- From the utilities window in macOS Recovery, select Disk Utility and click Continue.
- Select Macintosh HD in the sidebar of Disk Utility. Don't see Macintosh HD?
- Click the Erase button in the toolbar, then enter the requested details:
- Name: Continue to use Macintosh HD as the name, or enter a different name.
- Format: Continue to use APFS or Mac OS Extended (Journaled), as recommended by Disk Utility.
- Click Erase Volume Group. If you don't see this button, click Erase instead.
- If Find My is turned on for this Mac, you may be asked to enter your Apple ID to authorize the erase. Forgot your Apple ID?
- After the erase is done, select any other internal volumes that may be listed in the sidebar, then click the delete volume (–) button in the toolbar to delete each volume.
You don't need to delete the Macintosh HD volume you just erased, or any external volumes or disk images. - Quit Disk Utility to return to the utilities window.
- If you want to start up again from the disk you erased, you should now reinstall macOS on that disk.
If you don’t see Macintosh HD in Disk Utility
Your built-in startup disk should be the first item listed in the Disk Utility sidebar. It's named Macintosh HD, unless you changed its name. If you don't see it there, choose Apple menu > Shut Down, then unplug all nonessential devices from your Mac and try again.
If your disk still doesn't appear in Disk Utility, or Disk Utility reports that the erase process failed, your Mac might need service. If you need help, please contact Apple Support.
Learn more
Macbook Air Startup Disk Download
For more information about using Disk Utility, see the Disk Utility User Guide.