Much obliged, Gary. I'm guessing it has something to do with a system or software update, since older photos that had no problem before suddenly have a problem.
I'll look into PixInsight.
Has anyone had problems recently when opening unprocessed RAW picture files? For me, they open normally, but then suddenly turn grainy and the background color turns pinkish (e.g., the attached image of Capella). It even happens to my older picture files that did not look that way previously. It's nasty.
Google was no help, so I'm hoping someone here has had a similar experience and found a solution.