I will have access to the laptop only later to test these new thing I found: https://wiki.manjaro.org/index.php?title=Volume_Stuck_on_Mute_%28XFCE_Desktop%29
From: https://ubuntuforums.org/showthread.php?t=1796713 I may add a key in XFCE bindings looking like: amixer -c 0 set Speaker playback 100% unmute although the original poster was using Master not Speaker. Might try something from: http://unix.stackexchange.com/questions/124651/muting-and-unmuting-sound-with-mutebutton http://unix.stackexchange.com/questions/186269/alsa-mixer-unmute-problem-on-thinkpad-laptop For Lubuntu: http://askubuntu.com/questions/544754/lubuntu-14-04-unmute-sound-from-keyboard-not-work/757113#757113
