Hey, sorry for bumping. I also have a GMG key of ARMA II (not OA) and been in the process of activating the game through Steam since Tuesday. I contacted the support team regarding this issue and until now, they are asking me for the registry file of Operation Arrowhead. Thing is, I don't even have the expansion (never purchased) so I'm not sure what to do next. Also, I have never installed ARMA II when I first got it.