Switched in-game res from 4k to 1440/1080 - now can't bring game window back to focus

[jd]

Hi there,

My main external monitor is 4k but I generally run games on it at 1440 or 1080 as the machine is a laptop and the video card is fairly weak. In some games I'll go into the in-game settings, make the res change from 4k to 1440/1080, save, and then the game will smoothly keep rolling at the new res. Nothing weird happens.

Then there all the other games, such as No Man's Sky today (after the update), where I'll make the change from 4k to 1440/1080 and then the game window minimises/disappears, the Windows desktop and other open windows start resizing/moving around - across all three monitors, not just the one the game is running on. Visual chaos for a few seconds.

And then I find that while the game is still running, I can't bring focus to the game window for more than a second or two before it disappears again. Usually have to hard kill the game to close it. No Man's Sky example:
https://www.dropbox.com/s/ug2g8fpgj3lpqc5/Desktop%202021.04.01%20-%2016.42.19.02.mp4?dl=0

Anybody understand why that happens and how to deal with it?

Edit: for clarity - in that embedded video - I had previously made the 4k to 1440 change, then had the problem , killed the game, rebooted the pc, and was trying to re-launch the game - i.e. the game was already trying to start at 1440 rather than 4k.

Thx,
JD

[_I_]

run it at the native for the display
or use gpu control panle to center the non native res to the displays res
so the display does not need to stretch the image to fit its res