Reclaiming Disk Space from Old Windows Install
This is a quick post to describe how to reclaim disk space being used by an old Windows install. Recently, I upgraded to Windows 11 from Windows 10. I noticed that I was starting to run a bit low on disk space on my SSD. I have a 512 GB SSD and had less than 100 GB available:

I noticed that there is a folder named Windows.old that is 40 GB in size:

The instructions to reclaim the space seemed clear. Go to Settings -> System -> Storage and reclaim the space labeled as Previous Windows installation. However, ther was no such category when I tried:

After some searching and a little bit of thinking, I realized that this is probably a privileges problem. I became local admin by using the PAM tool. Then I ran the disk cleanup util as administrator:

I can now see that there are previous Windows installations:

I select to delete Previous Windows installations:

You have to confirm that it’s OK to delete:

The deletion process starts:

This will take some time…
There is now more space available:

If you’re running low on disk, check if you have previous Windows installations that you can Continue reading