Hello, I've been traversing through the Internetz trying to find this problem, and I've only come across a few posts on it, that didn't really help. Anyways, my problem is that whenever I join any DayZ servers, (Not sure if it happens to ALL servers however) it gives me " [Folder names...] are not signed in by a key accepted by this server. To play on this server, remove the listed files or install additional keys.''. I believe this problem occurs perhaps because I own the retail version of ArmA 2 and the steam version of Operation Arrowhead. With this is in mind, these two games are in two different directories. Now here's a few things I figured could be useful info : 1.) I have the latest Beta patch " ARMA2_OA_Build_92767.zip " 2.) I have started both ArmA 2 and OA individually once. 3.) When I start up OA through Steam, and press "Start Combined Ops", it does absolutely nothing. 4.) I do have the ArmA 2 launcher to start up Combined Operations, doing everything correctly including adding the DayZ as the addons and such. 5.) I have the most recent version of DayZ I know some things about computers, but its nice to have a step by step walkthrough for a fix if someone doesn't mind. Please ask me questions to help you guys out in figuring out a solution. Thanks Oh, here are some pictures of some stuff I have going on with this http://i.imgur.com/GuTvp.png <-- Launcher settings http://i.imgur.com/zsLQn.png <-- Error messgae I'm getting when joining a server. I hope this helps in any way.