just to be clear, windows 8.1 is unsupported. Windows 8.1U1 (Update 1) is supported. Thats more like a Windows 10 build increase than a service pack. Update

just to be clear, windows 8.1 is unsupported. Windows 8.1U1 (Update 1) is supported. Thats more like a Windows 10 build increase than a service pack. Update 1 uses the in place upgrade method to reinstall Windows. If you dont have Update 1 (which should have been called 8.2) you shouldnt expect software to target your environment.