If you upgrade your system to Windows 8.1, a copy of the previous version is stored on the drive. Why? To allow users to roll back to the previous version if the update wasn’t successful or you have a stubborn app that crashes in the new operating system.
If the problem is an app, you first want to run the compatibility assistant to troubleshoot it. If that doesn’t provide the fix, and you really must have it, then you still have the files to roll back.
If all is going well on your system, you will want to get some of that drive space back. Especially on a system with a low capacity drive and need as much space as possible. Here’s a look at how to get back your valuable disk space.
Usually to free up drive space you’d run the Disk Cleanup utility. But running it normally doesn’t scan the WinSxS folder located in the C:\Windows directory. That’s the directory where temporary files are stored in case you do need to rollback your system after a service pack or driver update for example. While the OS takes this action for the sake of reliability, it also collects a lot of outdated files and takes up a good chunk of drive space.
Now I suggest that if you have the time, wait a month or so before you delete the files because rolling back will become much more difficult when the files are gone. In fact it would require formatting the drive and you would lose all the work and data that you have on the Windows 8.1 installation.
So provided you are happy with Windows 8.1 and all apps are behaving then do the following to added gigabytes to your hard drive.
From the Start screen or desktop use the keyboard shortcut Windows key + R to bring up the Run dialog box. Then type: cleanmgr and hit Enter or click OK.
Next select the root drive (typically C:) that Windows is installed on.
The Disk Cleanup wizard will start and from here, don’t select the files you want to delete. Instead, click Clean Up System Files.
After the cleanup utility scans your drive you’ll get another set of results. Here is where you can get gigabytes of space back. Scroll down and check Previous Windows Installations, click OK, then confirm you want to delete files. In this example I was able to get over five gigabytes of drive space back after upgrading from Windows 7 to Windows 8.1.
This tip also works for Windows 7. For example, here I was able to clean up old service pack files and get over a gigabyte of storage space back.
Like I said earlier, you may not want to do this right away because you may indeed want to roll back your OS to that previous version. Some applications – especially legacy apps might not work in the new operating system. In that case you’ll be glad you didn’t delete the previous installations.