had the same problems you describe, it eventually stopped reading disc altogether, had read in here that others had same problem and had there nav-dvd drive replaced, took it to the dealer for service, and was told it was a problem with some X5s and they needed to replaced the drive (they had some on hand for that reason). They are doing it today actually, its a 08 E70, hope that sheds some light on it for you. Ill report back if I run into any problems