I can set any usable screen settings in Fallout 4 on my Windows 10.
Windowed mode can be stuck
and it can be unable to turn it off.
Next run it can be available, but resolution drop down can be empty
It is impossible to run Fallout in any combination. It can either run highly distorted and corrupted (see menu background):
or it can run partially occupying the desktop
Is it possible to get something consistent?
The issue is that you're using a 21:9 monitor, and Fallout 4 doesn't support that. You'll need to use the mod TruBy9 Ultrawide to allow it to work with this monitor aspect ratio, and manually set the isize W and isize H in (default location)Documents/My Games/Fallout 4/falloutprefs.ini to 3440x1440. Then keep in mind that any time you change your graphics settings you'll need to go back in and change the resolution in the ini.
