After upgrading to a new Windows 10 version, you will see two folders called $WINDOWS.~BT and $WINDOWS.~WS within the system drive, which is usually the C drive. These folders contain the files related to your older installation. Typically, the size of these folders will be anywhere from 15GB to 40GB depending on your system. As you can guess, that is a huge amount of space to be spared. If you are running out space on your hard drive or don't like wasting that much of space then you should consider deleting $WINDOWS.~BT and $WINDOWS.~WS folders for good. Let me show how to delete $WINDOWS.~BT and $WINDOWS.~WS folders in Windows 10.
What Are $WINDOWS.~BT and $WINDOWS.~WS Folders in Windows?
$WINDOWS.~BT and $WINDOWS.~WS folders are created when you upgrade from one Windows version to the other. For instance, when you upgrade from Creators update to Fall Creators update, these folders are automatically created with all the files relating to your previous Windows installation. $WINDOWS.~BT and $WINDOWS.~WS are used to help downgrade your Windows 10 machine to its previous version if you don't like the new version or if it is creating problems.
Now, you might be wondering what's the difference between $WINDOWS.~BT folder and $WINDOWS.~WS folder. It is as follows:
- The $WINDOWS.~BT contains files from your previous Windows 10 installation. So, when you try to downgrade or revert back to the older version, Windows will use files from this folder to restore the previous version.
- The $WINDOWS.~WS contains setup files downloaded by the Windows 10 Media Creator Tool. These are the setup files that help you upgrade your machine to the latest version of Windows.
So, if you are good with the current version of the Windows then you can reclaim a considerable amount of space by simply deleting Windows Bt and Windows Ws folders. In fact, in my case, I claimed back nearly 35GB space. Considering my 128GB SSD, that's is a pretty good chunk of usable space. One thing to keep in mind while deciding to delete these folders is that after deleting, you won't be able to downgrade to the previous Windows installation.
If you are good with that then proceed to know how to delete these folders. Just to be safe, create a system restore point too.
Delete $WINDOWS.~BT and $WINDOWS.~WS Folders
Note: After deleting these folders, you won't be able to go back or downgrade to the previous Windows version. Also, when you delete $WINDOWS.~BT folder, it will delete Windows.old folder too. Windows.old folder is also related to the previous Windows installation.
1. $WINDOWS.~BT and $WINDOWS.~WS folders are system folders. You cannot properly delete these folders using the delete key on your keyboard. You need to use the Disk Cleanup tool. Open Disk Clean-up tool by searching for it in the start menu.
2. Now, select "C" drive from the drop-down menu and click on the "Ok" button to continue.
3. As I said, these folders are system folders. So, click on the button "Clean up system files" button appearing at the bottom.
4. The above action will scan your system again for all the files that you can clean from your system. From the list, select the checkboxes next to "Previous Windows installation(s)" and "Temporary Windows installations files." Click on the "Ok" button to continue.
5. When prompted for confirmation, click on on the "Delete" button to delete $WINDOWS.~BT and $WINDOWS.~WS folders.
That's it. It is that simple. When you encounter these folders again after upgrading Windows, follow the same procedure to delete them. Also, do you know that you can move downloads folder in Windows to other partition or disk to free up even more space? Check it out to learn how to do it.