Try this:
1. In Mac Os, press Shift and the increase or decrease volume key 4 or 5 times. You should hear the clicking sound.
2. Press the Mute key in (Mac OS) several times. Do #1 above to retest. At some point the clicking will stop and the alert tone will sound. If not, try pressing Mute four or five more times, and doing #1 again until the clicking stops and the alert tone sounds.
This has worked for me, but always comes back after suspending and restarting the VM. Doing the above always works (again, for me.)
Last edited: Aug 20, 2014