Aaaaarrrrgh, this has been driving me batty for a week now. I recently did a clean 64bit installation of Xubuntu 12.04 followed by installing the Mate Desktop Environment. My only login to XFCE was the default one, which I used to install Mate. Logged out, then logged into the Mate session which is what I'm using full-time, primarily because of the file manager. I have just about everything working perfectly, except for the following:

Volume works great for mp3, movie, wav, and midi files. I have the volume control icon and I have the keyboard shortcuts for controlling volume levels. That's the stickler though ... because when I use the shortcut keys or the volume control symbol, the slider merely moves back and forth (up/down) without affecting the volume at all.

I did not have this problem with Xubuntu 11.04 but I think it started with 11.10. I have both, Alsa as well as Pulse installed. Alsa was the default and both appear to work just fine between login sessions. I have read what seems like hundreds of articles Online but most of them are about missing volume controls ... as opposed to volume controls that are there, but not working. Following the advice on numerous threads, I did make sure that gstreamer this and gstreamer that is installed properly. Like I said, the sound works just fine on all multimedia files, I just can't get the visual volume controls to work. Any ideas or fixes on this? Thanks in advance ...