Use Disk Utility to erase an Intel-based Mac
How to erase (format) the built-in startup disk of an Intel-based Mac.
Before erasing your Mac
If you want to restore your Mac to factory settings, such as to prepare it for a new owner, learn what to do before you sell, give away, or trade in your Mac.
Make a backup of any files that you want to keep. Erasing your Mac permanently deletes its files.
Use Disk Utility to erase 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.
If asked, select a user you know the password for, then enter their administrator password.
From the utilities window, 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: Macintosh HD
Format: APFS or Mac OS Extended (Journaled), as recommended by Disk Utility
Click Erase Volume Group. If this button isn't shown, click Erase instead.
If asked, enter your Apple ID. Forgot your Apple ID?
Optional: If you previously used Disk Utility to add internal volumes other than Macintosh HD, you can erase them individually using the same process.
When done, quit Disk Utility to return to the utilities window.
If you want your Mac to start up again from the volume you just you erased, select Reinstall macOS in the utilities window, then click Continue and follow the onscreen instructions. Learn more about reinstalling macOS.
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.
For more information about using Disk Utility, see the Disk Utility User Guide.