Technical Issue The "Video mode" (Changing the resolution) breaks my friends monitor

[Qyryss]

Changing the resolution completely breaks his monitor, he's tried to adjust it in windowed, full screen, windowed borderless, and every single time the changes completely fucks his monitor. (Picture provided: https://cdn.discordapp.com/attachments/547143932551757854/649714993121722371/image0.jpg )
Haven't a clue why, but he can't ALT - F4 the game, ctrl alt delete or even use his windows key, he has to hard-shut off his computer every single time.

 

[Spaghetti]

Probably a bad DPI change. Is the engine set to JAMP or MBII engine/OpenJK?

If it is OpenJK, open GameData and right click on mbii.x86.exe and go to its compatibility properties to override application scaling:

Then start the game and make sure whatever custom resolution you're trying to set matches the display's resolution exactly (typos will produce undesired resolutions...).