I take my SD card out of the D850 and plug it into the reader on my IMac. Click the "Get photos from camera" and in the little thumbnails that come up it looks like they are loading fine, I can see the photos I took. When I open the folder with the images, I see a bunch of .NEF files - not the usual photos. I click on one and it says Abobe can't recgonize this format. I've done this a lot, I don't think I changed any settings/etc. No idea what is going on. I get the same error with both cards. Same thing is happening with D500 files.