I know there have been a few issues with some SD card compatibility but I seem to a different issue.
I have a SanDisk 16Gb Extreme Pro CF card and all was working fine. Recently though the card reader stopped reading the card. It still worked with SD cards but could bot see the CF card at all.
So I started to transfer images direct from the camera using the lead provided.
I transfer using import on LR4, however there are always a few NEF images that will not transfer. I then try again selecting only the missing few and it then seems to import them okay.