El Capitan and missing volume control for speakers
I have just updated to OS 10.11 El Capitan. Upon successful completion of installation, my desktop speakers no longer have ANY volume control. I can not control the volume by the keyboard shortcuts on the keyboard nor by the volume control (which is now greyed out) in the menu bar. Note that I can select and use the USB speakers under the Sound portion of System Preferences, but I can not change the volume at all. Everything worked just fine BEFORE this update (which was a couple of hours ago). With the exception of the new OS, nothing else has changed on this computer.
Any thoughts on how I can correct this issue?
Mac Pro; 2 x 2.4 Quad Core; 14 GB RAM; OS 10.11 El Capitan
Speakers: Microsoft (yea, I know...) Digital Sound System 80