Loss of audio-input in Windows10 guests after rebooting guest (from 6.1.28)

[Nicolas@…]

Hello;

Starting with virtualbox 6.1.28 (tested as well on 6.1.30, 32, 34 so far) there is no audio input after rebooting a Windows 10 guest VM. The audio interface is present, but only silence as audio "in" after a reboot (audio was present at first boot). Everything was working well with virtualbox 6.1.26 or before.

The problem is easily reproduced at first try on any machine I have (tested several hardware, different sound cards, different CPU architecture amd or intel, different host os : debian 11 or windows). The problem always apear after the first (and any subsequent) reboot of the machine (either user induced, or due to and update or a VM crash).

Also tested several Windows 10 versions (LTSC ; entreprise ; home), all have the same problem. Depending on the host, I have tested several drivers (Alsa and PulseAudio on Linux and "Windows Direct Sound" on Windows). The problem is the same if the Guest Additions are installed or Not (therefore, not a problem with the GA).

Please see attached some logs taken with extended audio logs using options "VBOX_RELEASE_LOG=drv_host_audio.e.l.l2.l3.f+drv_audio.e.l.l2.l3.f+audio_mixer.e.l.l2.l3.f+dev_hda_codec.e.l.l2.l3.f+dev_hda.e.l.l2.l3.f+dev_ac97.e.l.l2.l3.f" :

File 6.1.30-Win10-NotOK-extended.log showing the problem :

• First test OK at 0:06s line 1445 "fMuted=true"
• Reboot at 0:41s line 1531
• Second test Not OK after reboot at 0:45s line 1729 "fMuted=true"

File "6.1.26-Win10-OK-extended.log" when everything is working fine with 6.1.26 for reference :

• First test OK at 0:08s. See logs line 1479 "fMuted=false"
• Reboot at 0:58 line 1559
• Second test OK after reboot at 1:02 line 1794 "fMuted=false"

Any help would be greatly appreciated :)

Thank you very much in advance !

[Nicolas@…]

Logs taken with a version having the problem (6.1.30 for example)

[Nicolas@…]

Logs taken with a version NOT having the problem (6.1.26 or before)

[Nicolas@…]

I need to add that if you properly stop the VM, then start it again, the sound is working fine... untill it reboots again.

[Nicolas@…]

Same Problem with Windows 11. It seems that when stopping the VM fMuted is switched to "True" and never unmuted when restarting...

[Nicolas@…]

Problem not corrected with virtualbox 6.1.36