Windows screen extend crash

Everything was working fine on my laptop (laptop more than capable to handle UE4) but as soon as I dragged UE4 to a second monitor, it started crashing whenever I use the laptop by itself, no extended screen. I have set the laptop to single screen, dragged UE4 back from second screen and unplugged second monitor, restarted UE4 but it still crashes a few seconds after starting up.
I have tried several other solutions to no avail. I cannot use UE4 without the second monitor, with UE4 dragged onto extended screen. Any help would be greatly appreciated! I cannot use the laptop by itself now, and I used to. Which means no remote work.