At this time, you can try to remove the sound card driver completely and reinstall your it again to see if it works. If there is a new version of driver released, please try it. Thanks. Nicholas Li - MSFT.
Programming the MPU-401 in UART mode., the information contained herein is only useful if you're writing an MPU-401 device driver for these. The Roland MPU-401 is a MIDI interface card for the IBM PC. Driver: Last Update: Availability: Downloads: Reported Installation Success Rate: Reported Reason for Installation failure: MPU-401 Compatible MIDI Device Driver for Windows 8: January 2013: Included in current bundle: 4: 100%.