Same problem. I've been using Switch to convert MIDI to MP3 for some time. I hadn't updated Switch but just recently the conversions started failing with exactly the message reported by the OP. Updating from 5.28 that I was using to 5.29 hasn't made any difference. I have the Creators' Update installed.
Conversion of The File Has Failed - to MP3
in Switch Sound Converter
Posted
Same problem. I've been using Switch to convert MIDI to MP3 for some time. I hadn't updated Switch but just recently the conversions started failing with exactly the message reported by the OP. Updating from 5.28 that I was using to 5.29 hasn't made any difference. I have the Creators' Update installed.