M6 will not shut down

When trying to shut down my player, I hold the play button as usual and the "shutting down" progress bar appears, but the player never shuts down. It then becomes non-responsive, but will still make click noises when I press buttons. I can do a reset by holding play and the forward arrow, but the same problem occurs after the player has reset. The only way I can get it to shut down is to wait for the battery to die, but the problem persists once the player is charged and I try to shut it down again. I have had my player for over a month and this just started happening yesterday. Any suggestions?

When the player gets non-responsive, you should be able to shut it down with a soft-reset (press the ENTER button until it turns off).
If you own a M6 SL it is the ON/OFF button. You have to press it for about 10-20 seconds.

Try updating your firmware. Instructions can be found in the FAQ.