OS X Mountain Lion: Remove Windows from your computer
You can use Boot Camp Assistant to remove Windows from your computer and restore your hard disk to a single partition.
- In OS X, quit all open apps and log out any other users on your computer.
- Open Boot Camp Assistant.
- Select “Remove Windows 7 or later version,” then click Continue.
If your computer has more than one internal hard disk, do one of the following:
If the disk with the Windows partition also contains an OS X partition, follow steps 1 and 2 above, then click “Create or remove a Windows partition.” Click Continue, select the disk with Windows on it, then select “Restore to a single Mac OS partition.”
If the disk with the Windows partition contains only the Windows partition, use Disk Utility to erase the disk and reformat it as an OS X volume.