:blink:I have a 4 gb memory stick pro duo that worked perfectly over the last few months but recently the prs 505 stopped reading it. I put all the books on the SD memory card which the prs reads perfectly.

What is going on and what can I do?

If you have all the book files backed up (as it sounds that you do), I'd suggest reformatting the memory stick and copying the files back to the memory stick and seeing if that works.

Then I'd see if another memory stick works in your 505, to determine if the problem is in the 505 or the memory stick.

thanks I will try it this weekend

There's also a good format to format it into, which is FAT I think but might be FAT32. Before formatting try deleting the Sony Configuration files (any that's not media) and then...then open up the card in libprs or the Sony software. I think that should kind of refresh the directory structure without having to reformat.