I am running build 8102 on Windows Server 2012 R2, PostgreSQL database, and am unable to apply the update pack. I get the following message in the command window from where I launch the Update Manager:

 

Error occurred :: Irrevertable exception occurred.

 

I am logged into the server with an admin account, and launch the command window as administrator. The current installation appears to run OK, so it does not appear to have broken anything, it just fails to install.