Hi, I have a '10 535xi with navigation and, for the 3rd time in almost 2 years all of the entries in the nav. system's address book have disappeared. All of my other settings, including all my "last destinations" remain. Is this a known bug and is there any way to recover the data. Also, from what I have read, it isn't possible to back up this data onto a USB drive via the USB port in the glove box. Is this correct? Thanks.