Just recently my version of Lightroom has become unresponsive when I try to import images from my Nikon D500. It behaves the same when I try either pugging the camera in via USB or using a card reader. It did work when I tried an SD card from my son's D7200, but locks up for the D500. I can copy the files via the Finder to the local hard drive and import from there, so I don't think the files are damaged, and the SD card appears on the Desktop just as it should. I've had the camera since May and it didn't happen until recently. Creative Cloud is all up to date, as is the OS. I'm stumped. Copying files is a work around, but not quick, nor how it should work. Any ideas?
Try the update to Lightroom 6.6.1, which claims to have fixed importing problems.
Could you please update Lightroom to latest version CC 2015.6.1 and let us know if that helps.You might have to Close all Adobe Apps followed by signing out and then Signing in to Creative Cloud App.
Refer the link Lightroom CC 2015.6.1 now available for more details.
A quick test show that might have worked. Cool! I'll shoot a few more images and try again. Thanks!