virtualbox.org

Yes, a dev has fixed 5.2 after I wrote my previous message.

and I am back,
so
I tried again and no sound
I found on a post that if I run the command VBoxManage modifyvm ubuntu-vm6-win
i get the available options. So on me I get:

[--audio none|null|oss|alsa|pulse]
[--audioin on|off]
[--audioout on|off]
[--audiocontroller ac97|hda|sb16]
[--audiocodec stac9700|ad1980|stac9221|sb16]

there is no coreauio for me
currently I have:
Audio: enabled (Driver: PulseAudio, Controller: HDA, Codec: STAC9221)
Audio playback: disabled
Audio capture: enabled

with no sound coming out.
again, I have
VBoxManage -version
5.2.28r130011

zal wrote:there is no coreauio for me

That is because the options for --audio are based on which host operating system you have. CoreAudio is a macOS feature whereas you have a Linux host so get Alsa, PulseAudio, etc.

zal wrote:VBoxManage -version
5.2.28r130011

As per the previous post from Socratis, I would head over to the Test Builds area and try the 5.2.31 build later than r131151.

-Andy.