Stalled Flash Player Install

I received the usual prompt today to update my Adobe Flash Player to the newest version, and duly clicked the link.   The download grinds to a halt 90% of the way into the install:

Thinking the link itself was the problem, I went straight to the Adobe site and tried the download from there.   Exactly the same thing happened.  I've never before had a problem before with Flash Player updates (running Mac OS X 10.11.5)   Anybody have any ideas?