Delete Windows.old folder after you install or Upgrade Windows
After installing or Upgrading to Windows 10 directly from the hard drive or virtual drive, you can notice that the C drive will occupy more space by Windows.old folder generated during the installation process.
Windows.old Folder saves the data of older versions of Windows (in order to restore windows), it's really not necessary to keep it and occupies more disk space. You need to wait 40 days after the system folder to be automatically removed, however if you want to remove this directory to regain the disk space, implement this method below.
Regain hard drive space after installing/upgrading windows.
1. Use the key combination ÿWindows + R.
2. Type in the dialog box
3. Select the drive C then OK
4. Select " Clean up system files "and wait for a moment to complete the system scan.
5. select Previous Windows installion (s).
6. Finally, click OK.
Method 2: Use the Command Promt
1. Run CMD with administrator rights ( Run as Administrator)
2. Type or copy and paste in this command: RD / S / Q% SystemDrive% \ windows.old andpress enter. Now check the results. Folder Windows.old has been removed from the system.