Hi again Keith. Well, this is very interesting. I tried again this morning to download using Image Capture -- no luck. Then, on your recommendation I tried Photos, and it did work. Well, that was good news, but I still want to continue to download raw files directly to my own personal filing system using Image Capture. So ... just for the heck of it I went to Image Capture again, and Voila! it worked. The app opened normally with the two small icons on the lower left, which had been missing previously.
Fantastic! Thank you very much, Cheers from Walter