I have problem with xfce mixer:
OS Russian Fedora 20
When i decrease the sound to 0% percent, mixer block the sound totally. This is good!
However, when I increase the sound, the sound does not appear.
For the emergence of sound I need open "Run Audio mixer":
and then press to "unmute Master" and so every time!
Please help! Thanks
I've found this happens too. Hadn't noticed it before as I have a a keyboard shortcut for mute and that works to mute and unmute.
It appears to be a bug, you could submit a bug report.
As a workaround create a shortcut with the command 'amixer set Master toggle -q'
If your system is using pulseaudio you can also try my plugin:
It's still a very early version but scrolling, middle button clicking on the plugin button, or using volume control keys works fine.