Update to my last Update - after going through extensive Driver updates - no change, still shutting down when opening a folder of NEF files. Oddly, though, if the folder was just JPG files the app stayed open but what's the fun in that, eh?
Then I focused on a new Transfer2 folder with just 38 shots, unlike the previous folders I have been trying to work in with many. many more files.
NX Studio works! More testing to come but I'm pleased with what it can do. It may be I just need to manage my storage "plan" and just use NX Studio with fewer files in the Folder.