Can you play music while charging?

I ran into this problem as well, and tried something that may work for you.  I was using mine through an FM transmitter to play through my car stereo.  When I hook it up to the USB port on the FM transmitter it turns on, connects to the FM transmiter through bluetooth and plays music but it the screen is locked at “transferring…” and none of the buttons function.  I tried turning the unit on under battery power first and get it playing music through the car stereo first, then plugging it into the USB outlet on the FM transmitter, then all of the buttons work as if it is still under battery power and the battery indicator icon shows that it is charging.  Hope that helps you out.