My PC's GPU is connected to my HDTV via HDMI. I often duplicate the display to both screens while I play games. I do this for reasons. Once or twice I had to fiddle with the resolution to get a different game to duplicate when fullscreen. Usually it involved using the maximum possible resolution. However, with Fallout 4 nothing is working.

No matter what resolution I run the game at, I will lose signal in one monitor when the game is run fullscreen. The signal comes back when I alt + tab or close the game. Aspect Ratio is grayed out and can't be changed. The display is duplicated when run in windowed or borderless windowed mode, but I worry about memory usage in that state. It's only with Fallout 4 that I have this problem. Even other Bethesda games like Skyrim and Fallout 3 work fine.

For reference, I'm running AMD Radeon R9 200 series. Is there settings somewhere I can fiddle with and fix this, or is there a problem with the game?

I expect it's a problem with the game. After the patch today, I can't even get the game to run in fullscreen at all, at any resolution. It just hangs on a black screen and spinning blue circle. I'm using Windows 7.

Oh, bummer. Thanks for the response though, that'll save me a lot of time fiddling with something that won't work.

No one has had success with duplicating, then?

Fullscreen in general seems to be very wonky.

I set Fallout4.exe and Fallout4Launcher.exe to run as administrator. After I did that I launched the game and the display successfully appeared on both monitors, but it dropped out on my primary monitor after the Bethesda logo.

Then, to check if it was fullscreen or bordered, I alt-tabbed and tabbed back in to find the display in the top left corner of the screen with green lines in the otherwise empty space. I couldn't move the mouse much.

Hey, sorry to bump this, but I really can't find anything about this anywhere. I tried to contact Bethesda support itself and I think I just got an instant automated message pointing me to an FAQ and the forums with no further promise of help?