This can happen if there is a problem with one of the DSP chips on an HD Core or Process cards.To determine which chip has the problem, do the following:Go to Windows>Show System Usage. Make a note of which DSP chip has D-Verb instantiated on it. Then in the mixer window, make all the plug-ins on that chip inactive by command-control clicking on them. Next allocate the same DSP chip by command clicking on it in the System Usage window. Reinstantiate D-Verb. It will allocate a different DSP chip you should not hear the oscillating, pulsing noise.