I lied. Here's my post before the help revamp: http://answers.ea.com/t5/Miscellaneous-Issues/Playing-abandoned-cities-in-downloaded-regions/m-p/4776868#M103118. Either way, I wanted to add a P.S. ... I only tried by creating a blank region to match the region with abandoned cities (i.e. A new Titan Gorge to copy a "blank city" to a Titan Gorge with abandoned cities.)
I imagine someone a lot smarter can take this and run with it? OH ... one more thing! It's a language thing. I tried to devipher the game file, and couldn't, but most definitely saw that the first glaring difference between my city's files and one I couldn't claim because I didn't own the content was the language "tag" ... for lack of a better word. A city I wanted to claim was Belarusian (BEL) where mine was english (ENG).
I wonder if I could install SimCity on my computer with another language pack and ... oh, what the hell, no way. Screw that. 🙂
-VH
