My Nikon D810 has SD and CD cards. The cards are configured to "mirror", not "overflow", so the SD card has a duplicate copy of everything written to the CD card. When I connect the camera to my Mac, and import into Lightroom, some duplicates are not imported, but some are. So I have to go through the entire folder and delete duplicates. I realize that I could remove the CD card and insert into a card reader, but I prefer not to subject my card to continuous removal and reinsertions. Is using a card reader my only option, or should Lightroom be smart enough to not copy exact duplicates? Also, the file names are the same except for a "-2" suffix on the duplicate file.