No sound from the audio system, and when this happens the DSP is not on or working, because the DSP Memory settings are not displayed. Happens several times a month. I have had the radio replaced, the head unit, and several other things without success. I was hoping this wasn't an issue on the M5 because I have not read about any problem like this before on the M5 board. BMW doesn't know of a fix, and apparently doesn't care. It is irritating, but not critical, that such an expensive radio doesn't have any sound occassionally, and that BMW feels this is a design flaw that we should be tolerant of. Good luck on guessing at what to replace to try to fix it, becasue BMW doesn't have a clue.