jrloader

This fixed the problem for me (thanks to Fully for the solution, and to Crocket for posting the problem), and to help Stickman007, this is exactly what I did: In Steam. Right click on Arma 2 Operation Arrowhead and select Properties. Copy the following text, including quotation marks: "-mod=Expansion\beta;Expansion\beta\Expansion;@DayZ;@rMod" -nosplash -world=empty Click on the "Set Launch Options" botton and paste the previously copied text into the box that pops up. I did the same for Arma 2 Operation Arrowhead beta. If you have the normal retail version, you should right click the shortcut, and paste the text at the end of the existing text in the target box.