Fix Stellaris unable to launch - Steam/Proton

gistfile1.txt

The game doesn't launch due to failed install of Paradox Launcher. 
After attempting to manually install by running msiexec on the same wine/proton prefix and failing,
I decided to install Europa Universalis IV, which is also a paradox game and copy over the launcher files from that game's compatdata (Program Files x64, AppData/Local and AppData/Roaming)
And that did the trick!

1. Install EU4 and Stellaris, make sure to force on both the same proton version (I used 6.3-7);
2. Hit Play on Stellaris, it will install multiple requirements then not launch;
3. Hit Play on EU4, it will do the same but eventually reach the Paradox Launcher;
2. The launcher will need to restart multiple times until it reaches the latest available version (atm it's 2021.8.1);
3. Close the game;
4. Head over to /steam_path/steamapps/compatdata/ and find the folders:
* Stellaris - 281990
* Europa Universalis IV - 236850
5. Head over to EU4's folder, then copy these folders:
pfx/
├── drive_c/
│   ├── Program Files
│   │   ├── Paradox Interactive                 <--- (1)
│   ├── users
│   │   ├── steamuser
│   |   │   ├── AppData
|   │   |   │   ├──Local
|   |   │   |   │   ├──Paradox Interactive      <--- (2)
|   │   |   │   ├──Roaming
|   │   |   │   |   ├──Paradox Interactive      <--- (3)
|   │   |   │   |   ├──paradox-launcher-v2      <--- (4)
6. Paste them (overwrite all) at the same locations but in Stellaris' folder. Make sure to maintain the same file structure
7. Hit Play on Stellaris

Note: This might also work if you can install any paradox game and it runs successfully, doesn't matter if it's Linux or Windows, just copy the folders to the same locations
    

Thanks for this, I didn't have another Paradox game but removing everything from compatdata/281990 forces steam to reinstall windows prerequisites which fixed the launcher. I guess reinstalling the game would have the same effect 🙃

Glad that it helped you! @yvdlima