>How about this solution, it worked in similar case: > > https://lists.debian.org/debian-user/2017/05/msg00467.html
I saw that discussion earlier, but if you follow the thread through you'll note that the claim of "solution" was a false alarm. I will give it a try none the less, since I am clutching at straws now. FYI - I just tested a brand new clean install, this time NOT using a local mirror during installation and it's the same problems again. I have to conclude that there's something wrong with the installation, at least for the combination of options I am choosing. I may have to go back to Jessie where I never had these kinds of problems.