An Important Disk Cleanup Job after Upgrading to Windows 8.1


If you are one of those who have upgraded from Windows 8 to Windows 8.1, there is a way to free up a lot of disk space. It makes use of a special setting in the Windows Disk Cleanup system utility.

When you upgrade to Windows 8.1, the previous Windows 8 files are saved in a special hidden system folder called "Windows.old". Added later: On some sytems the file is only marked Read-only. This is a backup in case something goes wrong with the upgrade. The old files take up several GB of space (on my system, nearly 6 GB). Once you are sure that the new Windows 8.1 system is working properly, there is no need to keep these files, especially if your disk space is limited. However, this special folder cannot be deleted in the usual way and here is how to remove the files. (But remember, once deleted, they cannot be recovered.)

  1. Open This PC (the new name for Computer)
  2. Right-click the system drive (usually C:)
  3. Select “Properties” in the context menu
  4. Click the button ”Disk Cleanup”
  5. Windows will take some time to do some calculations
  6. Click the button “Clean up system files”
  7. Windows will take some more time and do some more calculations
  8. A new tab “More Options” will be selected and an enlarged list presented. The graphic below is an example of the dialog box that appears
  9. Put a check by “Previous Windows installation(s)” and anything else you want to clean up
  10. Click “OK”
  11. You will be asked if you are sure you want to delete the files. Click “Delete files”

The cleanup will take some time. It may be best to let it run and not try to use the computer during the cleanup process. A similar procedure can be used for an upgrade from Windows 7.

Disk cleanup in Windows 8.1

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My experience was that only the PCs I updated from Windows 8.1 Preview to the final version of Windows 8.1 generated the "Previous Windows Installation(s)" files for cleanup. The PCs updated from Windows 8 to Windows 8.1 did not generate any files for cleanup.

Well, that is not what happened on my system.
On a tablet, I've upgraded from Windows 8 to 8.1 (Single Language version). It does have a Windows.old folder created. The properties of this folder show that it's not hidden, but ready-only. It contains more than 3,800 files inside the folder and sub-folders at a total size of 532 MB.
Thanks for the information about a tablet, Jojo. I added a note to the tip.

I'll probably stick with 'RD /S /Q %SystemDrive%\windows.old' in an elevated Command Prompt (presuming it's still allowed by 8.1). No waiting for disk scans.
Backup first, of course.

Have you actually tried to do that? The file is a protected system file.

Is there a reason not to burn this file I'm deleting to a DVD or save it to a thumb drive first?

Can is it intact? That is, can it be used from the flash drive?

And what if 8.1 does not work correctly? I have no smart devices so I already know that I do not know if win8 is working correctly--I'm just trying to manipulate it to a place where a non-using relative can use it and finding it not so easy. But then, I don't have anything with a touch screen and the entire concept makes no sense to me since I have great keyboard skill.

Even then, I don't even understand partitioning enough to know if this might be a good application for creating a partition and stowing a useless file away in a place never again to see the light of day unless disaster strikes.

I just hate getting old--or maybe it's just getting expensive.

There are several points to make. First, before any upgrade, you should always make a backup of the whole system. So I would hope you already have a backup. However, if you have plenty of disk space, there is no particular need to delete the file. People with an SSD or a small C: partition are the ones most likely to need the space. As to copying the file to another location, it is a hidden system file and copying such files and then reading them, if necessary, can be tricky. I have not tried doing that. If anybody has experience with that, let us know.