Remove Windows from your Mac using Boot Camp
You must use Boot Camp Assistant to remove Windows, or a partition that was created with Boot Camp Assistant, from your Mac.
WARNING: Do not use any other utilities to remove Windows or a partition that was created with Boot Camp.
Start up your Mac in macOS.
Back up all important data stored on your Windows partition before you remove Windows.
WARNING: When Windows is removed, the Windows partition—as well as all data stored in the partition—will be erased permanently.
Quit all open apps and log out any other users.
Open Boot Camp Assistant , then click Continue.
If the Select Tasks step appears, select “Remove Windows 7 or later version” or “Remove Windows 10 or later version,” then click Continue.
Do one of the following:
If your Mac has a single internal disk, click Restore.
If your Mac has multiple internal disks, select the Windows disk, select “Restore disk to a single macOS partition,” then click Continue.