When you upgrade your computer to Windows 10, you will see a new folder “Windows.old” in the C:drive or whichever the partition you chose to install Windows. Windows.old folder can eat up lot of hard disk space and is no longer used after the upgrade and so is safe to delete it. Windows just renames the earlier version of Windows that was installed on your PC before upgrade with extension .old and keeps it, just in case you decided to revert to your previous Windows. So if you have already made up you mind that Windows 10 is what you want to use in future, then you better off get rid of that .old folder to gain lot of lost hard disk space. When I say lot, it really is some 40 GB to 50 GB!
How to Delete it?
Even with Admin login, you can’t simply go and delete the folder due to security issues. Windows locks the folder using system rights and only Windows can delete it. The safest and easiest way to delete it is by using Windows built-in Disk Cleanup utility.
1. Type Disk Cleanup in the search box on taskbar and click on first result.
2. Click on “Clean up system files” button.
3. Make sure Previous Windows installations(s) option is checked. The size of it can vary from what is shown in my test PC. Usually, it is around 40 to 50 GB.
4. Windows will ask your confirmation to cleanup the system files. Go ahead and click “Delete files”.
5. Windows will now cleanup the Windows.old folder.
Did it work for you? Do let us know in comments below.