Unfortunately the “Automatic Update” documentation does not specify what happens in the event of a failure.
https://confluence.jetbrains.com/display/TCD10/Upgrade#Upgrade-AutomaticUpdate
It does state that “Create a backup of the current installation in the TeamCity home/.old directory.”
In the event of the failure, how do we restore to the state prior to the automatic update starting? Or is this all handled for us?