How to delete windows.old folder

Here's the proper way to delete the Windows.old folder:

If you upgraded your PC from a previous version of Windows, consider getting rid of this space-hogging folder

Did you upgrade your PC to Windows 10? If so, ever wonder what happened to the previous version of the OS? It probably disappeared into the mists of Windows past, right?
Wrong. Your old OS didn't get erased; rather, it's lingering in a system folder called, aptly enough, Windows.old. And depending on the size of that version, it could be hogging a lot of precious space.

How to Delete the Windows.old Folder to Free Up Space

The Windows.old folder can take up quite a bit of space. In a best case scenario, it might be 12 GB or so of hard disk space. But it could easily consume 20 GB, or a lot more — it depends on your previous Windows installation and how large it was.
Try to delete the Windows.old folder from File Explorer like you would any other folder and you’ll receive an error message. You could potentially bypass this error message by modifying with the Windows.old folder’s permissions. However, you shouldn’t bother with that — that’s not the correct way to remove this folder. Follow the follwing steps:
1) Right click on the C drive and click properties

2) Thereafter it will scan for the temp files available in the Drive.

3) Again it will search for the temporary files. Be patient.

4)Check the :Previous windows Installations and it will ask for the confirmation and click OK as provided below: