Windows 8/10: Recovering Disk Space After Upgrade

When upgrading from Windows 7 to Windows 8.x, or Windows 10, the upgrade places a backup of the previous operating system in C:\Windows.old. If the upgrade was successful and there is no expectation a rollback is required, and if space is a premium (for example on SSD drives), this folder can be removed using Disk Cleanup.

1. Choose Clean up System Files:
   

2. Tick Previous Windows Installation(s) and Temporary Windows Installation Files:
   

3. When prompted about being unable to revert to the previous operating system, choose OK.

To perform this manually (for highly technical users only):

1. Open an elevated command prompt.

2. Type:

   cd /d C:\Windows.old

   takeown /f *.* /a /r

   cacls *.* /t /g Everyone:F /c

   attrib -r -s -h *.* /s /d

   del *.* /s/q

3. Use Windows Explorer to delete the remaining files.