Over the past week I have been having problems importing pictures from my camera (Nikon D750) to Lightroom 5.7.1. After about a half dozen tries - shutting off camera, or unplugging cable, or restarting Lightroom I would be able to import pictures. Today, none of that worked. I even reinstalled Lightroom and still I can't import pictures. I can select D750 as the source, but LR says there are 0 Photos / 0 Bytes. Any suggestions?
Could you try to copy the images on the desktop and try to import the images from there. Check if you are able to import the images from there.
Get a card reader, that's much safer and more reliable for a number of reasons. Don't connect the camera directly by cable.
Aside from that, the card or the cable could be bad.
Just ordered a card reader. I will update the discussion when it arrives.
Karl M. Soehnlein