On Windows 10, a theme is a package that contains desktop wallpapers as well as a set of pre-configured settings, such as color scheme, sounds, cursor, and more to quickly change the look and feel of the desktop.
However, as you download more and more themes from Microsoft, these themes will pile up in the Settings app to the point that they will be unmanageable because the Themes page lacks of basic features, such as option to search, sort, and delete multiple themes at the same time (you can only delete one at a time).
If you have a lot of themes installed on your device, and you want to delete all or some of themes to make things more manageable, or you’re looking to free up some space, you can simply delete the packages from their source folder.
How to uninstall themes in bulk on Windows 10
Use these steps to uninstall all or multiple themes on Windows 10:
Search for Run and click the top result to open the command.
Type the following path and click the OK button.
Click the Home tab.
Under the “Select” section, click the Select all button. (Or select the themes that you don’t want manually.)
Under the “Organize” section, click the Delete button.
Once you complete the steps, the themes you selected will be removed from your computer, and they will no longer be available in the Theme page.