Now that you have upgraded to Windows 10 from your previous version of Windows operating system. This upgrading process will not only keep your files and programs from your previous versions but also keeps some of the OS files in a folder named Windows.old.
Windows.old folder takes a lot of memory of at most 20 GB(depends) roughly. Neither the old OS files are useful nor the memory taken by it. Literally, the memory taken by the Windows.old folder is a dump unless you want to downgrade back to your older Windows sometime in near future.
Note: If you wanted to test the new Windows 10 through the upgrade for sometime and decide later whether to have it continued, do not delete the Windows.old folder. It is only backup that helps you switch back to previous version easily.
However, 20 GB is not a small chunk of memory to leave it off. Those who really care about this amount of space better take a step forward to delete Windows.old folder.
Windows 10 is really an improved version of Windows OS and you won’t find any program incompatible issues with the software that was installed on your computer. So, I think you won’t find a necessity to downgrade back to older version again. It is always your choice anyway.
Removing Windows.old folder safely
Selecting the folder from the drive and hitting ‘Delete’ button is not the safe way of deleting the Windows.old folder. Using of command prompt to delete the folder is also not suggested.
To remove it safely from your system drive, better do it from ‘Disk Cleanup’ utility.
Step 1: Go to This PC > Right-click on Local Disk (C:) > Properties > Disk cleanup.
This won’t show up Windows.old folder in the ‘Files to delete’ options.
Step 2: Click on ‘Clean up system files’ button and that will scan for the unnecessary files on the drive with administrator rights.
This will then show up the Windows.old folder in the ‘files to download’ options.
Step 3: Select the ‘Previous Windows installation(s)’ folder and click ‘Ok’. It will then show you a warning saying that you can’t downgrade to the previous version of windows once deleted.
Step 4: Click ‘Ok’ to proceed. It will start the cleaning process right then.
That’s it. Check your Local Disk (C): now. You’ll find the partition regaining the 20 GB(appx).
*Local Disk(C): is considered as the operating system installed drive in this demonstration.