Was listening to a podcast in iTunes at my desk, left my desk briefly and as I sat down, the volume faded.
If I scrolled the volume back up, using my keyboard or the volume tray icon, it would smoothly scroll back down again.
I rebooted, same thing occurred.
Figuring maybe I had a stuck keyboard or hitherto undiscovered mouse function, I unplugged each in turn. Volume still wanted to go to zero!
Anyone know what might cause this? It's driving me nuts!