Jukebox messing up?

Knux

Like any "computer" you might have to reformat or reset the NAV. This may or may not delete your music libary(sorry)

I know there are hidden functions (service menu), It's somewhere on this forum, most likely somewhere in the Service manual.

While your in the service menu you can also change at which bit rate the music is recorded at. It's set by default to the higher one, if you have a lot of music you might consider changing it to the lower bit rate, ( I dont think I would be able to tell the difference while driving). There were a couple of other functions in that menu, I just can't remember.