Hi - This is likely an outlier - I'm hoping the team can fix. If I set TSW to Full screen 5120x2160, and exit the game, when I come back on my monitor displays a message saying it's only being fed a 3440x1440 signal. If I set the Windows mode to 'Windowed FullScreen' (and hit apply) it will start outputting 5120x2160, after that If I set the mode back to FullScreen (and hit apply) it will stay at 5120x2160 (as confirmed in my monitors info panel) It's then fine until I restart the game. For the Curious, the monitor is the LG 34" 34WK95U-W It is basically a widescreen version of a 27" 4k Monitor.
Hi Jack, Could you send us a DxDiag so we have a better understanding of your system. As your issue could be down to something outside the game like Geforce Experience amending your settings automatically when you close the game: https://dovetailgames.kayako.com/Knowledgebase/Article/View/176/0/how-to-create-a-dxdiag-report https://dovetailgames.kayako.com/Tickets/Submit