Keep having to hit middle button to play files in car

Basically I have to power off and on the Sansa each time I enter the car.  The files will only play if I hit the middle button whilst repowering, like on the computer.  Is there anyway to make this stay as default so they get recognised without this?

Thanks for the read

Go into Settings>System Settings and change the USB mode to MSC. That should  take care of it.

Cheers mate thats hit the spot.