After upgrading my Windows 10 installation to the Anniversary Update, I noticed that I had two windows folders; windows & windows.old. Both were eating up a lot of disk space, but I had no clue if I could safely delete the windows.old folder.
The windows.old folder contains all information about your previous windows version. Idea is that if you want to roll back to the old version, it’s possible through the recovery option. Windows will automatically clean up the old folder after some time but if you can’t wait here is a (safe) alternative:
- Open Windows Explorer.
- Right click on the drive that contains your Windows installation. Choose Properties.
- Click the Disk Cleanup button on the General tab.
- After the Disk Cleanup tool is done calculating, click on the Cleanup System Files button.
- Select the Previous Windows Installation(s) option to delete the Windows.old folder
Remark: I noticed that if you don’t run the Disk Cleanup tool as an administrator, the Previous Windows Installation(s) option is not available.