[2021] Cannot launch CK3

In the game launcher please set Display mode to windowed.THEN go here:

Latest supported Visual C++ Redistributable downloads

This article lists the download links for the latest versions of Visual C++ Redistributable packages. support.microsoft.com And run the x86 and x64 installers there.

IF that doesn't help, Has the game ever run OK on this computer? Or never?

IF NEVER:
Install ALL these Microsoft modules:

Download Microsoft Visual C++ 2010 Service Pack 1 Redistributable Package MFC Security Update from Official Microsoft Download Center

www.microsoft.com

Download Microsoft Visual C++ 2015 Redistributable Update 3 RC from Official Microsoft Download Center

www.microsoft.com

Download DirectX End-User Runtimes (June 2010) from Official Microsoft Download Center

www.microsoft.com (run dxsetup.exe after extracting from this download)

Add CK3.exe to the exceptions list of your antivirus app; ESPECIALLY if you have Windows Defender, add it to the Ransomware "Apps Allowed Through" list.


IF IT USED TO WORK:
Please do a full **clean** re-install:

- move any valued save games elsewhere
- "uninstall" in Steam-CK3
- manually delete both the Steam/SteamApps/common/CK3 AND Documents/Paradox Interactive/CK3 folders
- re-install game in Steam, run a Steam Verify when done.
- add CK3.exe to the exceptions list of your antivirus app; ESPECIALLY if you have Windows Defender, add it to the Ransomware "Apps Allowed Through" list.
- start the game with no mods active and test

In particular make sure there are no files or folders left under either the Steam CK3 or Documents CK3 locations, before installing again.


If those don't help:
DXDIAG is a program you run from the Windows search box on the task bar. After running it will open a window and start collecting info with a progress bar in the lower-left corner. When it completes click the 'save all information' button and save it to a file then attach that file here.

Please attach here your Documents/Paradox Interactive/CK3/pdx_settings.txt .
From your Documents/Paradox Interactive/CK3/logs/ folder, attach here system.log , error.log  

No obvious cause for this problem there I'm afraid.

If you run ck3.exe directly from File Explorer, what happens? Any Windows error show up?  

I've seen that a bit with EU4 but not CK3, until now anyway.

You're not running ck3.exe as the Windows Admin user, are you?


What antivirus app do you use? You need to make sure all these apps are in its exceptions lists:

ck3.exe (in the Steam CK3/binaries folder)
dowser.exe (in the Steam CK3/launcher folder)
C:/users//AppData/Local/Programs/Paradox Interactive/launcher-v2.2021.10.1/paradox launcher.exe
C:/users//AppData/Local/Programs/Paradox Interactive/bootstrapper-v2.exe

IF that does not help, also set all those .exe files (EXCEPT ck3.exe!) to run as the Windows Admin user.