Thank you for the quick reply. Before installing MP4, I decided to monitor Task Manager and identified the following Windows Process as the culprit:
Microsoft Compatibility Telemetry
Upon booting into windows, MP 3 works fine. But once this Windows process starts, MP3 stops working completely. Forcing termination of this Windows process resulted in restoration of full MP3 function. I have been able to reproduce this a few times now successfully.
I was not able to find any known documentation of this Windows process casuing issues with MP3. The Microsoft Compatibility Telemetry is specific to Windows 10 (and is not a virus), but is related to how MS collects user data. Although MP3 is being phased out it seems, I would keep it on the backburner that this process could be causing issues with MP3 and possibly 4.