20 days ago - AndrewT - Direct link
Delete the following folders if still present:

- C:/users//AppData/Local/Programs/Paradox Interactive/
- C:/users//AppData/Local/Paradox Interactive/
- C:/users//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//AppData/Local/Paradox Interactive/launcher-v2/
Please attach them here.

Note that you can run eu4.exe directly from File Explorer, which bypasses the launcher.