The only issue I have had with either of mine (I have two of them) is that one of them stopped playing custom announcements. That issue was corrected by removing the microSD card and then reinstalling it. You might try using the "Configure" and "Refresh" button in the driver to see if that helps.
Update. After several days of waiting, the battery finally died and it got plugged in again. Successfully restarted and now operating correctly. Damn that was annoying.