A problem with the head units we hear about quite often is that a CD installed in the unit will not eject. There is a small rubber bumper inside the unit that rests on the CD when its not in use. If the CD is left in the unit for more than a day and not played, the rubber bumper can become fused with the CD due to heat in warmer climates. Sometimes the CD can be ejected once the system cools down, but many times youll have to disassemble the unit to break the rubber bumper loose from the CD. Chris at Corvette Clinic says its best to simply remove the CD when you wont be listening to it for a while.