virtualbox.org

I had sound working just fine with a Win 2K guest and a Kubuntu 8.04 host. But after the most recent reboot, it quit. Specifically, I got the message Some audio devices [PCM_out] could not be opened. The message also instructed Check the logfile for error messages of the audio subsystem. But what logfile does this refer to, and where can I find it?

I'm using PulseAudio and ACH 97. Using other host drivers had a different effect: substituting the null driver.

This error is particularly mysterious because I wasn't aware of changing anything before the most recent reboot. I might have done a system update (the usual one), though I'm not sure, but that shouldn't account for the problem. Just before the reboot I lost the keyboard (even CapsLock didn't work) but I don't see how that would be relevant.

I've had that when I've been using an audio application on the host
and then tried to use another audio application on the guest (Ubuntu
8.04 host, W2K guest). Even after the original host application had
ended I still couldn't use sound from the guest.
I don't recall if it always happened, or if there are just some
applications that don't work well together. In the end I gave up
trying to share the audio resources and NULL'd out the sound driver
on the guest.
I also tried installing a USB based, external, audio device that was
mapped through to the guest - but that didn't work too well either:
the sound was too choppy to be recognisable.

What if you use ALSA for audio instead of PulseAudio? PulseAudio is quite new, so there are sure to be bugs here and there, and it seems that this is one of them. See if switching to ALSA fixes it. If it does, it's probably a problem with PulseAudio and not VB.

Alsa sound doesn't work for me in Vbox -- I get the message that the null driver is being used instead. OSS doesn't work either. But I solved my Vbox sound problems, along with some other sound problems, by executing the command alsactl store, which I learned about from another forum.