I also have trouble, sometimes it crashes randomly ingame, sometimes it crashes in the loadingscreen. When it crashes in the loadingscreen it is impossible to join back until the server restarts (maybe something weird in the Server Cache). I reinstalled ArmA3 4 times, including twice through Steam and through the complete windows PC version. None of this fixed the issue for me.

Everything happens on a Altis Life server. I know other player have also this issue.

There a 2 Different types of crashes.

1: ArmA crash randomly ingame. Nothing much to say, just a new window with "ArmA 3 don't work anymore"

2: ArmA crash while loading the game. When this happen once on the Server is it impossible to join the server *till* restart. I think its a issue with broken data in the server cache. (Just a little note I got this issue also in A2 on my own server)