I try to back up my files using Windows 8.1 file history in System and Security>File History. The default drive is to one letter belonging to a USB stick. I am not able to select another drive. The USB stick does not have the storage required to save my back up files. How am able to change my drive in File History? I tried select another drive. That doesn't work. The second storage device I use is not being found by windows to change the drive.