I have had Debian 9 running on my Desktop for years. Sound is configured fine, but I did it a very long time and installed JACK and many other things. Summing up, it's complicated.

Now I have a fresh Debian 9 installed as a virtual machine in VirtualBox. Sound does not work. When I try to play a WAV file in Audacious, it tries, but halts as soon as it begins to play. Under Settings, only ALSA is accepted. Everything else causes error messages.

I also tried playing the WAV file with mpv. Again, it begins to play then halts.

What can I do to have sound using ALSA? I really absolutely prefer ALSA.

TIA

It might help to know what things you've tried and what those error messages were. That might provides some hints as to where else to look.

I didn't really try much because I don't know what to try. I want ALSA. I don't want the other sound architectures.

The general answer is: just install it.
We have no idea what did you install/configure in the past. Summing up, it's complicated.
VM will make these things even more difficult. So would be nice to know more about it.
If I have to guess it is a VM related issue, but I can't read your mind and also can't access your computer.

Yes, but there should be steps to troubleshoot an audio problem...

yes, you are right. First of all you need to check log files, look for error messages. Understand and handle those messages.....
What do you expect now from LQ ?

Steps to troubleshoot my audio problem...

ok, so if you need help the first step is describe your problem better. see post #2, #4 or http://www.catb.org/~esr/faqs/smart-...html#beprecise

Without details we are not able to give you any help. The very first thing would be to post the mentioned error messages (in post #1). There a lot of different possibilities (if it was the VM or inside the VM or ???).

If you want to solve it alone the first step is to look for log files and/or error messages (post #6).