"The rebuild operation is ignore!" - what does that mean?

I get the following error message when trying to start my M6: "The rebuild operation is ignore! The system is instable before rebo". It's still possible to load the player - the display shows the battery loading and, after some time, that it's full.
Does anybody have any ideas?

I've never seen (or read about) this message before- i think the text is cut off the screen's border and it should be:
"The rebuild operation is ignored! The system is instable before reboot".

If you cannot turn the player on, the only thing you can do is to try the usual steps:

1. Hard reset
2. (low level) Formatting
3. DFU-Tools

I've already tried the usual things (hard reset etc.), but nothing works. The only time the player does anything is when it's connected to the computer and starts loading the battery (I can even hear "click, click, click" when I press buttons). Then I also sometimes get the error message, but not alway. Once disconnected, there's no reaction when I press the power button, play or any other button in any combination.

If you can hear the clicks the player must be frozen (and still turned on), so if you can't force it to shutdown (by soft reset) keep it disconnected from PC and wait until the battery is empty.