I dont know for what reason ArmA needs 2-3 minutes (sometimes more) until its closed. When I close ArmA I can see in Task Manager how the used RAM is getting lower very slow.
I my opionion Arma should just save the current confings and just kill the own process like the taskmanager does.
Dont know whether its depening on hardware, thats why I added the dxdiag. {F24452}