So I'm having the same issue as everyone else. However, I've noticed that each time I attempt to load DayZ, Arma and Arma 2 seem to lose files as a result. You can observe this by attempting to play bootcamp following quitting from the "Loading character screen" This is fixed by right clicking arma in steam, going to properties, local files and then click verify cache. Doing this for both games allows you to play anything but dayz. However, upon attempting to relog into a dayZ server will result in having to restore these files all over again. One of the afflicted files is the battle eye service. I hope this is of some help to the guys trying to fix this.