Problems with audio on Windows 10 guest

[itm]

I have a Windows 10 x64 guest running on a Windows 10 x64 host (Virtualbox v6.1.30). The audio frequently (but not always) stops working. It usually seems to happen when I power up a 2nd USB audio interface on the host while the guest VM is running. The USB audio interface is a Behringer UMC404HD. Today, however, the USB audio interface is not powered up and still I can't get any audio in the Windows 10 guest VM.

The host machine is a Gigabyte B450 Aorus Elite with a Ryzen 7 CPU and 32GB RAM.

My audio settings for the guest are:
- Enable audio - checked
- Host audio driver - Windows Directsound (the only alternative available is "Null Audio Driver")
- Audio controller - Intel HD Audio (the alternatives are "ICH AC97" and "Soundblaster 16"). I've tried the ICH97 option but still don't get any audio
- Extended Features:
- Enable Audio Output - checked
- Enable Audio Input - checked

When the audio stops working on the guest there is no visual indication of any problems in the settings - i.e. the audio adapter is enabled etc). I've tried uninstalling and reinstalling the audio device in the guest but it doesn't help.

Any idea why the audio might be failing so frequently?

[scottgus1]

Start the VM from full normal shutdown, not save-state. Run until you see the problem happen, then shut down the VM from within the VM's OS if possible. If not possible, close the Virtualbox window for the VM with the Power Off option set.

Right-click the VM in the main Virtualbox window's VM list, choose Show Log. Save the far left tab's log, zip it, and post the zip file, using the forum's Upload Attachment tab.

Please note that I personally ight not know how to fix this, but the log may help a forum audio guru know what to do.