Try using the File Manager for your OS to Copy the images from the SD card to your hard drive and into a folder of your choice. Then open LR and see if you can Add them to the catalog through the import dialog window.
Also go into the LR preferences and turn off the option to "Use Graphics Processor".
I did turn off the graphics processor in Lightroom, but it did not correct the issue. Lightroom still will not recognize the compact Flash card in my "G" drive (card reader). Funny, because when I use my Canon 5D Mark II, and put that into the card ready - no problem.
When I try to "import" with images from the 5DSr, Lightroom basically freezes.
The computer works fine out of Lightroom - and I do have the new version Lightroom 6.3 uploaded.
This is driving me bonkers.
Do I have to re-install a previous version, or un-install, or have to call Adobe in the AM for technical support. I am not a CC subscriber - I bought the program by itself.
Thanks for your help.
Have you checked whether your operating system see that CF card in the reader?
Have you tried a different CF card in the camera? Could be the one you are now using is bad. Or even a SD card in the camera?
If you are using a UDMA 7 CF Card you will need a reader that supports UDMA 7 and USB 3.
Older card readers do not support the newer format cards.
Note: I described the same in the previous thread you were posting in.