Sharkhead

Here's the guaranteed solution (no thanks to you guys : P ) Don't just hit uninstall for Arma 3 in Steam. Manually delete the entire Arma 3 folder so no files remain afterward. You want a 100% fresh install, at least fresher than Steam usually gives you, cause it won't delete the Arma 3 folder, just most of the installed files. This guarantees that you will no longer experience this issue. As for causes, a friend suggested it could have to do with a server script corrupting my client, but we don't know.

Arma 3 ran fine the first two days I had it. Then out of the blue I get this: I googled for an answer, found none. Quick assistance is greatly appreciated since my holiday has just begun and I would like to get down to alphatesting as soon as possible ^__^