I had MSI enabled for both audio and video on my Nvidia card a while back, but I don't use the VM often and didn't notice it was gone until the 'demonic' audio came back last week. Manually adding the 'MSISupported' entry in the registry worked like a charm for video/display, but I just couldn't get the audio to enable after dozens of registry updates and reboots. Then I came across this post and tried the MSI Utility tool, which of course worked like a dream.
So if anyone else has gone through the steps to manually enable MSI on your Nvidia and it never sticks, this tool is your salvation! Thanks!