When your machine is upgraded to a newer version of Windows, it leaves behind a C:\Windows.old directory which can be quite large.

It contains the backup of the previous Windows version, so if you plan on deleting it you’re saying goodbye to the rollback option.

If do you try delete it, you’ll likely encounter the following…

Try again please…

We can remove this by running Disk Cleanup.

Click Clean up system files.

(might take a sec)

Select Previous Windows installation(s) and click OK.

You are sure, so click to Delete Files on the above prompt.

As mentioned, if you delete these files you’ll lose the ability to restore back to the previous version of Windows. You’d peer check before going ahead with this in the workplace.

It might take a good 5 minutes or so.

When it finishes you should see the Windows.old files disappear and the disk space be freed!