Fatal Application Exit - Unknown Game File (mscorlib.dll)

[DarlingDeirdre]

I haven't played Rust in a few months but last time I played everything was working fine. I tried to play it yesterday and after loading EAC I'd get this message: Fatal Application Exit - Unknown Game File (mscorlib.dll)

I verified the integrity of the game files - Didn't work.
I reinstalled Rust - Didn't work.
I opened a cmd in administrator and ran sfc /scannow - Didn't work.
I reinstalled Steam and Rust - It worked for the day... But this morning I tried to play again and I'm getting the same error.

I'm running Windows 7 Home Premium.