A:Answer I've never had this problem, but I do know that unplugging any device from a computer improperly can cause problems including losing data. From the sound of it, it may have lost some of the formatting. Without knowing more about your problem, I would suggest simply powering it down with the little switch on top, wait a few seconds and turn it back on. Maybe even try plugging it back into the computer, letting it fully charge (that could also be the problem) and then properly disconnect it from the computer by using the "disconnect player" app on the tool bar at the lower right. That has worked for me when I've turned it off in the middle of an audio.
