Just got my car few days ago and this has happened to me 2 times already - googled it, and I see from this post that I´m not the only one..
Bummer!!
Will check with my dealer in Norway tomorrow..
Both times I´ve been listening to music from the harddrive, downloaded by me from regular audio files off a cd..
My last BMW (an E92) had to replace the head unit after only a few months because of a similar problem so this starts off great....... Grrr.