Windows Operating System upgrades, as well as version updates, would leave plenty of files behind in the system drive. This is because Windows keeps the files from previous versions of Windows in a separate folder, in case the user wants to roll back the major update (or OS upgrade).
For instance, the Windows 10 feature updates give you 10 days time to rollback to the previous build or version if needed. After 10 days, the option to go back wouldn’t be available as the respective folders are cleared automatically. If you’ve upgraded to Windows 10 from Windows 7 or 8, the previous Windows installation folder (Windows.old) is retained for 30 days.
After the stipulated time (10 days), the corresponding folders will be wiped out automatically by Windows. These are the folders that would be emptied automatically:
- Windows10Upgrade (this applies if you used the upgrade assistant tool)
If Windows doesn’t automatically clear those folders, you can use Disk Cleanup or Storage Settings to remove Windows.old and the other folders. This article explains how to delete the Windows.old folder using 3 different ways.
Clearing the Windows.old (Previous Windows versions) folder in Windows 10
How to Delete the Windows.old folder (Previous versions of Windows) in Windows 10
After Installing a major update or Feature update, you can immediately free Up 20 GB+ disk space if you don’t plan to rollback the update. Typically, the amount of disk space freed up might be anywhere between 14 GB to 25 GB depending upon the bitness of your Windows installation, and the number of programs installed in the system drive.
Using one of the following methods to delete the Windows.old folder on your system drive.
To delete the Windows.old folder using Disk Cleanup, follow these steps:
- Start Disk Cleanup by running cleanmgr.exe via the Run dialog.
- Disk Cleanup (cleanmgr.exe) doesn’t list Previous Windows installation option if you’re not running it as administrator. So, you’ll need to elevate it by clicking Clean up system files button in the Disk Cleanup window.Or, you can run it as administrator from the Start menu. To do so, click Start, type Disk Cleanup, and right-click Disk Cleanup from the results and choose Run as administrator.
- In the next dialog that appears, select the following check boxes if available:
- Previous Windows installation(s)
- Temporary Windows installation files
- Windows Upgrade log files
If the Disk Cleanup utility doesn’t list the Previous Windows installation(s) entry, or it throws up an error when cleaning up, use Windows 10’s Storage Settings app (as in Method 2 below) to clean up previous versions of Windows folder.
The Storage Settings (or Storage Sense) app helps you cleanup temporary files, empty the recycle bin and the downloads folder at regular intervals. Other than that, the Storage Sense also lets you delete the Previous Windows installation (“Previous versions of Windows” files) easily.
- Click Start → Settings → System → Storage
- Click Change how we free up space automatically
- Scroll down to the Free up space now section.
- Select the Delete previous versions of Windows checkbox, and click Clean now.
Setting description: These let your PC go back to a previous version of Windows. We delete them automatically in 10 days.
Clean up starts immediately. You won’t be asked for a confirmation.
Editor’s note: Previous version of Windows stuff occupies at least 25 GB of space. In the above screenshot, it shows 3.22 GB because I’ve manually cleared stuff from the Windows.old folder prior to running the Storage settings app. So in your case, space freed up will be much…much higher. In my test system where it showed 27 GB used by Previous version of Windows (upgraded from Windows 7 x64), it took around 7 minutes for the Storage settings app to assess and clear the Windows.old folder.
Windows.old using Disk Cleanup or Storage Settings sounds very easy, but they fail to clear the folder in some situations. If they don’t work in your case, you should be able to delete the Windows.old folder manually with the required folder permissions.
- Right-click Start, click Command Prompt (Admin)
- Type the following commands and press ENTER after each command:
TAKEOWN /F C:\Windows.old /R /D Y icacls C:\Windows.old /grant administrators:F /T
The above is to take ownership of
Windows.old, its sub-directories and all the files within and assign full control Permissions for the
Administratorsgroup. So the process might take some time to complete.
- Then, run the following command to remove the
RD /S C:\Windows.old
RD /S \\?\C:\Windows.old
Now, the option to Go back to an earlier build should be dimmed out.
If you’re unable to empty Windows.old folder using any of the above methods, then it could be caused by the
LocalState.. folder having invalid characters in the file name and remains inaccessible or undeletable.
To wipe out the Windows.old folder along with the Cortana\LocalState.. sub-folder successfully, you have two options:
- Use the DOS device path — i.e., with the
\\?\prefix. For example, to delete the Windows.old folder using DOS device path, use the following command from an administrator Command Prompt.
RD /S \\?\C:\Windows.old
- Use Unlocker as described in the article How to Delete a Stubborn Undeletable File or Folder in Windows?
That’s it! Hope you’ve reclaimed disk space by removing the
Windows.old folder on your Windows 10 computer using one of the above methods in this article.
About the author
Ramesh Srinivasan founded Winhelponline.com back in 2005. He is passionate about Microsoft technologies and has a vast experience in Windows — delivering support for Microsoft's consumer products. He has been a Microsoft MVP (2003-2012) who contributes to various Windows support forums.