I am changing book data using Calibre (author name, tabs etc..) but it doesn't seem to always work first time - i.e. I make the change, then unplug the PRS-505 and the changes only seem to work about 2 thirds of the time. They will always work eventually if I do it again, but it's a bit annoying. Pretty sure this must be me doing something stupid, so any advice gratefully received.