Answer by Raffa for Ubuntu 18.04: Audio doesn't work unless I switch between outputs

Option 1

Please, run in the terminal:

sudo alsa force-reload

This will reload ALSA sound driver modules in case they were modified by an upgrade, reinstall or install for example and the old ones are still in use as users tend to avoid reboots sometimes or do not think a reboot is needed after such upgrades.

Option 2

Please, run in the terminal:

alsamixer

You will then be presented with a screen like this:

Please, check if the speakers or any audio output is muted and unmute it.

MM means mute and OO means unmute.

Then exit when done by pressing Esc

Option 3

Old pulseaudio configuration files can sometimes get corrupted or conflict with newer versions of pulseaudio after package / system upgrades. To fix this please follow the steps below:

• Back up ~/.config/pulse/ configuration directory to ~/.config/pulse_old/ by running the following command in the terminal:

  mv  ~/.config/pulse/ ~/.config/pulse_old/

• After that, reboot your system to build new pulseaudio configuration files. A new ~/.config/pulse/ directory will be created automatically.

• Test your audio now.

If, somehow, after applying this fix you decide to go back to the previous state before applying the fix, please follow the steps below:

1. Run the following command in the terminal:

   rm -r  ~/.config/pulse/

2. Run the following command in the terminal:

   mv  ~/.config/pulse_old/ ~/.config/pulse/

3. Reboot your system.

However, if all is okay and the problem is fixed, you can remove the backed up old configuration directory ~/.config/pulse_old/ to free space ( if you wish ) by running the following command in the terminal:

rm -r  ~/.config/pulse_old/