Thanks to Marco for the advice, and special thanks to Henri for additional support.
As noted on https://cygwin.com/ml/cygwin/2020-01/msg00129.html, my problem was due to installing Cygwin in the drive root. I was forced to do this some years ago because of a third-party package that required Cygwin to be installed there. Following a suggestion from Henri, I moved C:\bin, etc. to C:\Cygwin and then ran setup with the latter as the installation directory. I could then apply the 3.1.X update without problems. -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
