Download from Roland the driver archive for Windows 8.1.Please see the comments (below) for how to do this. Remember also you must set your Windows installation NOT to enforce driver signing. And, indeed, when you install Windows 10 onto a machine with the UM-1X plugged in, it remains unrecognised by the new operating system. Roland, who make the venerable MIDI to USB interface the UM-1, and its more recent version the UM-1X, claim that they will not support Windows 10.