Have a look at the stickies at the top of this forum section.
Your player is most likely memory
hacked, to show a larger capacity than it actually has.
The follow this method here -->
How To: Removing Memory Hack.
It will not recover the missing files, but it will prevent this from happening in the future.
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For my dreams i hold my life...
I miss my Meizu M6SL... Currently rocking a Sony Ericsson w595 on Samsung in-ear phones. Does fine, but it's not a chipod...