Randomly during multiplayer the game will freeze, it could be within 5 seconds, 20 minutes or an hour. So I uninstalled Arma 3 all together, removing all mods, etc. Did fresh install which allowed me to play for about 30 mins before freeze. I think the longest I have ever played is around 1 hour before freezing.
Windows shows error "Arma 3 has stopped working. A problem caused the program to stop working correctly. Windows will close the program and notify you if a solution is available."
This also happens in single player but only very rarely.