If you upgrade your Windows 7/8 to Windows 10, or you upgrade Windows 10 to the latest version, you will have a Windows.old folder saved on your C drive. This folder is used to roll back to the previous version of your Windows. However, if you are satisfied with the current operating system, probably you want to delete Windows.old, which usually takes 10 GB around disk space.
So what we are going to talk about is how to delete Windows.old folder.
Probably you may wonder: I select Windows.old, choose Delete, but the deletion failed. Why I can’t delete Windows.old folder? Here we would like to say that Windows.old is regarded as system protection files, hence you can’t simply remove this folder by the Delete option from the right-click window, and you will need permission from system.
Here two ways are introduced here:
Way 1. Use Disk Cleanup
Search “disk cleanup” at Start. Then choose “Disk Clean-up” from the best match.
You will see a window allowing choosing a drive to clean. Here C drive is selected by default, so you just keep this option and hit OK to continue.
Disk Clean-up will automatically scan the drive and calculate how much disk space is able to be released. Then a Disk Clean-up for C: window appears where you should check the “Previous Windows installation(s)” to clean.
Disk Clean-up will ask you whether you want to permanently delete these files, confirm the deletion. One more time you are warned that you will no longer be able to restore the machine back to the previous version of Windows if you delete Windows.old. Click Yes.
Way 2. Use CMD
Press “Win + X” to call out the power user task menu. Then select “Command Prompt (Admin)” and allow it to take control of your PC.
In the command prompt window, type “RD /S /Q %SystemDrive%\windows.old” and hit Enter. Then Windows.old folder will be deleted.
By using these two ways, you should be able to delete Windows.old without any obstacles.
It is worth mentioning that Windows.old only lives for 30 days, then it will be deleted by Microsoft Windows. Hence, you will lose the chance to roll back to the previous Windows if you do not have a backup. Here we recommend you make a backup of your system and then use the backup copy to downgrade OS. In this way, you get two operating systems.
Please download MiniTool Partition Wizard Free and then make use of its Migrate OS to SSD/HD feature. For the detailed steps, please refer to Downgrade Windows 10 to the Previous Version.
Next, boot computer from the backup copy, and use Windows Recovery to go back to the previous version.
When Windows finishes, you get both the previous operating system and the updated OS. Now you don’t need to worry about the 30 days roll-back limit.