"Failed to open main.cs". how do i fix it?

So: I start the game, the game stops working and tells me it doesn't find main.cs. Does my PC suck too much or am i doing something wrong?

I verified the Integrity, meaning all the Data should be there, tried re-installing countless times and removed my mods so maybe it could work. I had that problem before but it resolved due to an unknown reason.

So: What should i do?

 

I am on Steam

 

So i've tried anything really, i tried to find my Anti-Virus, instead i found Windows defender and de-activated scanning on the BeamNG folders. then i proceeded to check if any files were missing, there weren't that steam said. Also i checked Integrity on BeamNG and on the steam settings page to see if really everything is there. Unfortunatly i opened it again today and there was still no success. i honestly don't know why main.cs wouldn't want to open. Either it has trouble finding the file in my folder or the main.cs Data is broken which shouldn't be possible

 

Funny thing is, i tried the 32-bit version and that works perfectly fine.