If forcing the resolution through Steam does not work, the game's local configuration file might be corrupted. Deleting this file forces Serious Sam 3 to generate a brand-new file with default settings upon the next boot.
If deleting the file does not work, or if you prefer to keep your other settings, you can manually edit the file to match your monitor's resolution. serious sam 3 cannot set display mode
Use Ctrl + F to search for gfx_bFullScreen and change its value to 0 to force windowed mode: gfx_bFullScreen = 0; Use code with caution. If forcing the resolution through Steam does not
Note: Once the game boots successfully to the main menu, you can go into the in-game graphics settings, set your correct native resolution, change it back to Fullscreen, and remove the launch option. 2. Delete or Reset the Configuration File Use Ctrl + F to search for gfx_bFullScreen
Find the game's main executable file (usually located in the Bin or Bin\x64 folder, named ). Right-click Sam3.exe and select Properties . Go to the Compatibility tab. Check the box for "Run this program as an administrator" .