Feedbacker
100+ Head-Fier
@Relic
EDIT : something really bothers me.... i copied around 20Gb of files again on this card, i browse and try to play them in Foobar, no problem. I put the card in the X5, browse it and discover than most of the folders are empty !!! no music found. I put the card back in the PC and folders are still empty now.... like the X5 damaged the indexes or something, and i haven't even tried to build the library. So now files are there... just invisible... (but the card remaining free space shows that the files should still be there).
This sounds like a fake card. I was unlucky to have a couple of them, and they behaved exactly like you describe...