So Microsoft released Windows 10 to the world back on 29 July. Many of us went ahead and pressed that upgrade button.
And then we all wondered where 20 GB went.
The upgrade process to Windows 10 actually allows you to revert back to a previous version of Windows – you probably noticed you had a C:\Windows.old directory sitting around on your hard drive. Some of you might have thought to yourselves, “I don’t need that, I’ll just delete it.” STOP!
Don’t do that.
Go press the Start Button (yay it’s back!!!) and type in Disk Cleanup. Disk Cleanup will pop open and you’ll say to yourself, I want all the disk space back I can get – mind you, you can’t revert back to your previous version of Windows if you do this. . . Click on the button in the bottom left that says something about Administrative System Files. Disk Cleanup will go and run a scan of things not initially presented which include, “Previous Windows Installation(s)”.
If you want to reclaim the space and have already scavenged the Windows.old directory for items that may not have been dropped in your Documents folder or Desktop folder and are ready to commit to expunging those files, click the check box and then okay.
You’ll get another pop up, and you’ll confirm it and boom, you’re on your way to reclaiming some hard drive space.
There’s a Microsoft support page, though oddly it’s written for Windows 8.1.
http://windows.microsoft.com/en-us/windows-8/how-remove-windows-old-folder
The Tech Blog of Dan Usher 