Windows.old folder gets created when you upgrade your Windows installation to a newer version of Windows operating system, when you install Windows on an existing version of Windows without formatting the drive, or when you perform a Refresh operation.
If you are having Windows.old folder under the root of your Windows 10 installed drive, it’s either because you have upgraded from Windows 7/8 to Windows 10 or performed clean installation of Windows 10 without formatting the drive containing previous Windows installation files.
The Windows.old folder contains all files and apps from the previous Windows installation. The Windows installer uses this folder when you want to downgrade to the previous version of Windows or when the installation of a newer version of Windows fails to complete.
Since the Windows.old folder contains all Windows operating system files and installed apps, it takes significant amount of disk space. In some cases, the Windows.old folder size might go up to 10 to 15 GB, depending on the total size of previous Windows installation.
Users who have installed Windows on a smaller SSD drive or users who don’t have allocated significant amount of disk space to the Windows installed drive might want to delete or remove Windows.old folder to gain some valuable disk space.
But Windows.old folder can’t be easily deleted by right-clicking on it and then clicking the Delete button.
So how to delete Windows.old folder to free up disk space in Windows 10? There are couple of ways out there to delete Windows.old folder. You can either use the native Disk Cleanup tool or use third-party free tools like CCleaner for the job.
Follow the instructions in one of the below mentioned methods to get rid of the Windows.old folder and free up GBs of disk space in Windows 10.
WARNING: Don’t delete Windows.old folder if you have plans to revert to previous version of Windows. That is, if you have upgraded your Windows 7/8 installation to Windows 10 and now planning to downgrade to Windows 7/8 again for some reasons, don’t even think of deleting Windows.old folder as downgrade operation can’t be performed without the Windows.old folder.
Method 1 of 3
Delete Windows.old folder in Windows 10 using Disk Cleanup
Step 1: Open up This PC. Right-click on the drive where Windows is installed and click Properties.
Step 2: Under the General tab, click the small Disk Cleanup button to run the same. And if the Disk Cleanup button is not appearing as shown in the picture below, please refer to our Disk cleanup missing from drive properties in Windows 10 guide to restore the same.
Step 3: Once the Disk Cleanup utility shows the following dialog box, simply click the Clean up system files button to begin the scan.
Step 4: Finally, when you see the following dialog, look for the entry named Previous Windows installation(s) or Windows.old folder. Check Previous Windows installation files or Windows.old folder, and then click OK button to delete the Windows.old folder.
The Windows.old folder should no longer appear under the root of Windows installed drive.
Method 2 of 3
Removing Windows.old folder using CCleaner
If the Disk Cleanup tool isn’t listing Windows.old folder, you could take the help of popular CCleaner software to delete it.
Step 1: Download and install CCleaner software if it is not already installed on your PC. You can download the latest version of CCleaner for Windows 10 from here.
Step 2: Run CCleaner, click on the Cleaner tile in sidebar, and uncheck all options except Old Windows Installation on the right side under Windows and Applications if you are interested in deleting only Windows.old folder.
Step 3: Click Analyze button to begin the scan. Once done you’ll see Old Windows Installation and its size on the right-side. Click Run cleaner button to delete the Windows.old folder from your Windows 10 PC.
Method 3 of 3
Delete Windows.old folder in Windows 10 using Command Prompt
Step 1: Open elevated Command Prompt. To do so, type CMD in taskbar search box or Start search box and then simultaneously press Ctrl+Shift+Enter keys to open Command Prompt as administrator. Click Yes button when you see the UAC dialog.
Step 2: In the Command Prompt, paste the following command and then press Enter key to delete Windows.old folder.
RD /S /Q %SystemDrive%\windows.old
If you’re getting any error, make sure that you launched the Command Prompt as administrator. Good luck!