When Arma crashes, is this after you've selected the slot, when it's loading up the map? Also, when Arma crashes, is it a soft crash/lock up? If so, one potential solution to these problems can be to delete the contents (save the readme) if your Arma 3 DLL folder. In this folder are Arma 3's memory allocation .dll files. The soft crashing/locking up seems mostly linked to the memory it's allocating, borking up.
Give it a shot (verifying your game cache will cause the files to be re-downloaded), and if you still have the issue, it's at least something to cross off your list.