Re: One user can't log in
Thank for the responses, Nate, Svein, and Shyamal.
My /home directory partition is about two years old and has been through
many cycles of various linux distro installations and removals without
reformatting and seems to have accumulated some strange files besides
having messed-up groups.
Rather than trying to eliminate these flaws one at a time, I decided
to simply clean the /home partition by reformatting and starting over.
I've aleady done this and the problem of one user not being able to
log on is gone. The group assignments are now correct.