I had the odd situation happen when I received a call and then attempted to use the radio. No sound would emit from the speakers except for phone calls no matter what I did. I tried a restart but that did not work. I called BMW assist and they recommended a 10 minute off period to reset the system. I tried that and all was well. Just wanted to pass this along in case this happens to you. The microcode must be similar to MS Vista OS, reboot frequently.