My mod XML was a mess, built as it grew. There was no consistent order or system to the XML or files, though it worked. I decided to start by fixing units. A unit might have a different name in Unit ClassInfos, UnitInfos, UnitArtInfos, the Art File, and the nif. The button might be on an atlas, in interfaces/buttons or in the unit art file, and miight be named not to match.

So, I set out to clean it up. I organized everthing by what it was, with all the barbarian units, then all the workers, then all the settlers, etc...In the art, I organized it by where I got the art, who the author was. I created a consistent way of doing everything all the way through, got rid of duplicate and obsolete files and tested it out. I squared all the changes with all the necessary files, CivInfos, GoodyInfos etc...

This played great up until modern times, then I got a crash. On troubleshooting, I found that the crash occured whenever Madrid completed what it was building. I switched civ to play as spain and found that when I went to the city screen for Madrid, it was corrupted: I could not see what buildings were in the city or what was available to build, but I could move citizens around.

Further investigating, I found that Madrid was the first city to contain a corporation. Further testing, I found that this occured in any city with a corporation. First a flawed city screen, then a crash on completion of building anything.

All I had messed with was units. Nothing to do with corporations or city screens.

Without these changes, no problem. Any suggestions about what might have caused this?

Did you mess with the corporation units much that might of caused the crash?

Sure enough, the late era art definition for the executives. Thought it was redundant because the primary use existed with a different name. What a strange consequence, though. Normally when an art definition is missing you just get a straight CTD when it is completed, not a loss of city screen where it is available.