keep getting buffer over run have reinstalled and then delete the launcher directory in the Arma 3 directory, then I've re-verify the integrity of your game cache
this was happening a fair bit.
Uninstall the game.
I made a backup of Arma 3 folder in Documents.
Delete both Arma 3 folders in Documents and Steam:
\Users*YOUR USERNAME*\Documents\Arma 3
)\Steam\SteamApps\common\Arma 3
Reboot your PC.
Run Steam as Admin, download the game.
Try to run Arma 3 (without mods).
then deleted the arma 3 and steam and redownload the entire game