This appears to be a duplicate of Bug #878986 and a problem with pulse audio. using pactl instead is a solution that worked for me. As documented here. http://askubuntu.com/questions/118675/mute-key-mutes-alsa-and-pulseaudio-but-unmutes-only-alsa
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1026331 Title: `amixer set Master toggle` mutes but doesn't unmute To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/alsa-utils/+bug/1026331/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
