I have recently upgraded to LR4. Love it. However I am now starting to use my old 5Dc again for the summer and when I connect the camera to the PC with a USB cable, the import previews are empty and just say "Preview Not Available".
My 5D2 works fine.
Putting the 5Dc card in a card reader works fine.
The 5D2 even shows the previews when I put the card from the 5Dc in (with images taken by the 5Dc) - so the images aren't the problem.
I prefer to connect the camera by USB as I dont want to be continually removing and re-inserting the CF card.
The issue really is that it was working on LR3 and only failed since I've moved to LR4.
Is this something I've got to live with or is there something I can do, like re-install drivers, etc? I have already purged the RAW cache and that made no difference.