We generally do not recommend installing the update if Microsoft has not offered it for your PC. But if you have installed the May 2020 update using Windows Update, the previous version of Windows will be saved in Windows.old folder in the system drive. If the latest update is working fine, there is no need to keep this folder as it takes a lot of system space and becomes annoying especially if you have less space in the C drive. Please note that if you remove this installation data, you will not be able to downgrade it to the previous version of Windows (which is not required unless the system gets very unstable) There are two ways to delete all the previous installation files safely. We will discuss both of them here.
Delete previous Windows installation using Storage Sense
To delete the previous Windows installation data, follow the instructions below:
Delete previous Windows installation using Storage Sense Remove previous Windows installation using command-line
Open Windows Settings by going to the Start Menu and clicking on the settings icon. This is just above the Power icon. You can also use Windows key + i keyboard shortcut key to open Windows Settings directly. Now click on the System settings and then click on Storage from the left-hand menu. From the right-hand pane, click on Configure Storage Sense or run it now. This will open the Storage Sense configuration window. Under Free up space now, check Delete previous versions of Windows. Press the Clean now button. This will run the cleanup program and remove all traces of the previous Windows installation.
Remove previous Windows installation using command-line
You can also remove the previous Windows installation data using the command-line. Open the command prompt in Administrative mode by going to the Start Menu and searching for cmd. Select Run as Administrator from its menu. Simply run the following command. Please note that it may take a few minutes to complete. Do not close the command prompt window until you get the next prompt. If you do not delete the Windows.old folder, it will automatically be deleted by Storage Sense after 10 days of installation. If you are a fan of CCleaner, it can also clean up the previous Windows installation folder.