(K)Ubuntu 17.10 - No Audio devices found, no settings, no sound

I just installed Kubuntu 17.10 (reinstall, from 17.04), keeping my old /home, but formatting/reinstall to /boot and /

When it started up after installing, I noticed the sound icon in tray being the "speaker + red line", indicating no sound. Systray Sound Icon > Dropdown say:

no output or input devices found

In Settings, I can't change anything related to audio since the system claims there's nothing there. Settings > Multimedia > Audio Volume. No ouput/input device found.

Strangely enough, Spotify and VLC is making sounds. But not Firefox, not Pillars of Eternity (Steam (Flatpak)). And nothing show up in settings. Those pics were taken while playing music in Spotify.

If I open Volume Control (Menu > Multimedia > PulseAudio Volume Control), I get a box displaying the following message:

Connection to PulseAudio failed. Automatic retry in 5s. In this case this is likely because PULSE_SERVER in the Environment/X11 Root Window Properties or default-server in client.conf is misconfigures. The situation can also arise when PulseAudio crashed and left stale details in the X11 Root Window. If this is the case, then PulseAudio should autospawn again, or if this is not configured you should run start-pulseaudio-x11 manually.

These was no countdown (5s), but the window did blink twice to something to the effect of "trying to connect to PulseAudio". Nothing happend after that.

I tried start-pulseaudio-x11. Output:

Connection failure: Connection refused
pa_context_connect() failed: Connection refused

My sound device is connected via standard Jack (normal speakers). No HDMI or anything. Two monitors connected via DP. Had no problems with it on 17.04.

I tried the following, from an old question: mv ~/.pulse ~/.pulse_backup

Result: mv: cannot stat '/home/USER/.pulse': No such file or directory

TL;DR: Audio doesn't work after installing Kubuntu 17.10 (/home from 17.04). No settings available in audio Settings. Sound from VLC and Spotify, but not Firefox, game/steam. Error message say PulseAudio failed.

I had the same problem and seeing the logs in /var/log/syslog I had an error for pulseaudio daemon:

[pulseaudio] module.c: Module "module-switch-on-connect" should be loaded once at most. Refusing to load.

So I opened /etc/pulse/default.pa and edited it using # to disable 3 lines:

#.ifexists module-switch-on-connect.so
#load-module module-switch-on-connect
#.endif

Maybe it'ś not the best solution but it solved my trouble.

I have solved this by reinstalling pulseaudio.

Pay attention: if you have some custom edits inside /etc/pulse, they get lost if executing rm -rf /etc/pulse as shown below! In my case there are only a hand full of files that have been reinstalled.

Update 2019: take care if package plasma-desktop is uninstalled while removing pulseaudio. Reinstall before booting, otherwise your system may not boot properly.

• apt-get remove --purge pulseaudio
• rm -rf /etc/pulse (maybe remove $HOME/.config/pulse also)
• apt-get install pulseaudio
• apt-get install plasma-desktop
• reboot

This also deinstalled some other packages (like oss*) which have not been reinstalled, and in my case, I don't miss them at all. ;)

[EDIT]

If your card is listed by something like sudo aplay -l, but not listed in pavucontrol, your card may be blocked by further processes. Check that sudo fuser -v /dev/snd/* doesn't list any other processes than pulseaudio. In my case when upgrading to kubuntu 19.04 it was blocked by squeezelite process, so I stopped and disabled squeezelite and everything was fine:

$ sudo fuser -v /dev/snd/*
/dev/snd/controlC0: root  872 F..... squeezelite
/dev/snd/pcmC0D0p:  root  872 F....m squeezelite
[... bad ...]
$ sudo systemctl disable squeezelite
$ sudo systemctl stop squeezelite
$ pulseaudio -k
$ sudo fuser -v /dev/snd/*
/dev/snd/controlC0: myUsername 1459 F..... pulseaudio
[... good ...]
$ pavucontrol

... et voila! My soundcard is available inside pavucontrol again.