The game will cause the whole system to freeze, requiring a hard reboot. I have tried 301.xx-314.xx drivers with the same result. In A2 this happens when the game's refresh rate does not match my desktop refresh rate, but in A3 it appears to have the same crash behavior regardless of refresh rate.
Workaround: If I find myself alt-tabbed, I simply force close A3 via the Taskbar or TaskManager. If I need to change the resolution, I do so in the config file.
Similarly, this happens to me in the latest Beta versions of A2 if the game runs at a refresh rate other than 60hz. {F17081} {F17082}