I had the same error on a site that was a clean install of 9.0 with base modules. I manually updated that site and I can't be certain I tried every permutation of every suggestion posts. Certainly most of them.  On the others, there were very slight modifications - no more than 10 lines and I could go through every single file and compare it to the full list of UNA files on Github.  Even adding them to a database would be insane.  No files were replaced and I assume the unzip went fine. There are a few files on the sites unrelated to UNA- notes mostly.  

I don't have 100 or more hours to debug what is most likely a UNA issue. I have done that before.  I want to start working on the websites instead of UNA files and application related issues. develop a rudimentary custom design in the time I have spent n UNA. 

It is a waste of time and energy.  I will figure out something for the one site still on UNA and if the next update fails - mover on to another app. 

Still, thanks for the posts. It does help and I appreciate them.