In Windows 10/8.1 OS, there is also another problem: When you uninstall a built in app, the uninstall process does not completely remove the app from the system, because the app's installation files (aka 'Provisioned Packages') and its leftovers, are not deleted during the uninstall. Some of these preinstalled apps (also known as built in apps), can be easily uninstalled from the system, by right clicking on them and choosing uninstall, but many built in apps cannot be uninstalled by using this way, and you have to uninstall them by using PowerShell commands. As you may know, Windows 10 comes with many apps preinstalled.