I stil get error #2 (Game Security violation Detected (#0000000C), though I don't have any listed software. What can be done in order to fix it?
Taken from EAC technical support page;
Game Security Violation
The game process or system's integrity has been compromised and the game will exit. This is usually caused by outdated or insecure background third party software. To resolve this, update or disable background third party software and restart your PC.
So try to double check the task manager, make sure non of the suggested applications is running such as LightingService.exe, though the list is not limited to those applications. Possibly outdated ShadowPlay may cause issues.
If that doesn't work, repair EAC as shown in Problem #1 then try Problem #4 suggested solutions followed by restart.