I recently upgraded my Dell E6510 laptop to 12.04 (Ubuntu with Unity). I've noticed that after every reboot, the volume always resets itself to a maximum level.
While I try to work out whether this is a bug, I'd like to know if there is something I can do at login or startup that will mute (or perhaps just reduce) the system volume.
After checking reverendj1's answer, I tried
pacmd set-sink-volume 0 0 and then
sudo alsactl store, after the first command failed to work.
I also did a right-click on the volume indicator and went to Sound Settings..." -- from there, I selected Built-in Audio Analog Output on the Output tab (it was my only choice, but it wasn't highlighted for some reason).
During this troubleshooting process, I rebooted a few times. I'm not 100% sure whether any of the Analog Output settings had ever been altered from the install defaults, but I'm documenting the setting for posterity, in case someone else runs into this: