Failed Upgrade 5.6.39 -. 5.6.41 Now Mysql service will not start

[Steve Longmire]

I tried to update the MySQL community Edition 5.6.39 using the MySQL Installer to 5.6.40. All the connectors, etc updated, and it looked like the MySQL Server did as well - until it got to the configuration stage. There I entered the root password and hit check and then the MySQL Installer froze up - saying (Not Responding) - Waited for 30 minutes but it never recovered. So I have rebooted the WSE 2012 server and tried to run the MySQL Installer again - it offered to reconfigure the MySQL Server but the same thing happens again.

The c:\Program Files\MySQL\MySQL Server 5.6\mysql.exe is version 5.6.41 now.

I can't see anything that strikes me in the error log.

How can I roll back to what was working before or fix this one?