if you use MTP mode, it requires more free or “head” space to operate than MSC mode. I always use MSC and also have had less than 10mb (in fact, sometimes kb) free on the player and also the card.
I remember one time I was trying to help someone here and was attempting to duplicate his problem that required me to use MTP mode. All of a sudden, I got the dreaded “Not enough space for Music DB. Please free 90MB” error msg.
End result, I formatted the player (which erased everything), reset to MSC mode and re-loaded the player.
