Removing Windows.old Folder via Command Prompt Once the Disk Cleanup finishes, the C:\Windows.Old folder would be deleted. Select “ Previous Windows Installation(s)” and click on “ OK.” Disk Clean-up again calculates space occupied by System files that can be deleted. If the UAC window pops up, choose “ Yes”. The wizard then shows the various folders that can be emptied to free space on your drive.
Windows calculates the amount of space that you can free on C drive. The Properties window shows the used and free space on the C drive.