OK, so I just had another Adobe pop-up window appear on my Mac saying I need to update Flash. I figured why not give it another try, so I did and the installation worked this time. I have not changed anything on my Macbook Pro, so it appears that Adobe has fixed the problem, whatever it was. I am now running Flash v.184.108.40.206. Not sure if that is the same or a different version from the one they sent last week that would not install. It's just incredible to me that they don't do a better job of testing this stuff before they just throw it out there to the entire public. How can that even happen? Not a very positive reflection on the management of this company.