Please run these Windows repair tools:
.NET
Describes the .NET Framework Repair Tool and how to obtain it.
support.microsoft.com
SCANNOW:
Describes how to use the System File Checker tool to troubleshoot missing or corrupted system files in Windows 8.1, Windows 8, Windows 7 or Windows Vista.
support.microsoft.com
THEN Please try this:
- uninstall Paradox Launcher v2 from the Windows "Apps and features" utility, if still present.
Delete the following folders if still present:
- C:/users/{userName}/AppData/Local/Programs/Paradox Interactive/
- C:/users/{userName}/AppData/Local/Paradox Interactive/
- C:/users/{userName}/AppData/Roaming/Paradox Interactive/launcher-v2/
To see the AppData folder you'll need to enable View Hidden Items in File Explorer.
- exit the Steam app entirely
- run steam.exe as the Windows Admin user
- run the game from the PLAY button in Steam
OR
- exit the Epic app entirely
- run EpicGamesLauncher.exe as the Windows Admin user
- run the game from the Epic client
IF that doesn't help, in this folder are some .log files:
C:/users/{userName}/AppData/Local/Paradox Interactive/launcher-v2/
Please attach them here.
Note that you can run ck3.exe directly from File Explorer, which bypasses the launcher.