Medfly 1 Posted December 31, 2011 I recently bought ArmA II: Combined Ops off of Steam. I used to have ArmA II: Free but deleted it in fear of corrupting files. After installing both OA and II I can play OA singleplayer and make private multiplayer matches but when I join anyone elses game it starts throwing out missing files for vehicles and buildings, mostly. Upon, starting ArmA II I get a message saying the following: "Bad Serial number given in setup". I've been perplexed by this issue all day, and I'm becoming very frustrated. Share this post Link to post Share on other sites
