[2021] Another version of this product is already installed.

Please try uninstalling the Paradox Launcher from the control panel. If it won't go, use the free utilities Revo Uninstaller and Ccleaner to do that.

THEN Please try this:

- exit the Steam app entirely

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.

- run steam.exe as the Windows Admin user

- run the game from the PLAY button in Steam

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 stellaris.exe directly from Windows Explorer, which bypasses the launcher.  

Tolodociro said: I'm having the same issue
I followed your advice but still getting the error on startup
Here are the log files, please help I want to play with some mods.

Please do not re-open old threads in future. As the fix for the OP here did not help you, clearly you do not have the same problem.


The 1603/1605 errors we see there are typically a previous other installation stuck, or a problem in the Windows update/install processes.

If you see msiexec running in Task manager-processes, kill it and try this launcher install again please.

Otherwise run the Update app in Windows, does it load okay, find anything to apply - whether a patch, update, or whole new Windows 10 version? If so do that and reboot, then try this launcher install again please.

If still no good, do you see Paradox Launcher v2 in the Windows Control Panel to uninstall? If so does it uninstall cleanly, or get an error doing that? You can use this MS tool to clear the stuck install/uninstall:

Fix problems that block programs from being installed or removed

The Program Install and Uninstall troubleshooter helps you automatically repair issues when you're blocked from installing or removing programs. support.microsoft.com

IF that doesn't help, in this folder are some .log files:
C:/users//AppData/Local/Paradox Interactive/launcher-v2/
Please attach them here.  

Ah, that is usually an antivirus app getting in the way. What antivirus app do you use? You need to make sure all these apps are in its exceptions lists:

stellaris.exe and dowser.exe (in the Steam Stellaris folder)
C:/users//AppData/Local/Programs/Paradox Interactive/launcher-v2.2022.10/paradox launcher.exe
C:/users//AppData/Local/Programs/Paradox Interactive/bootstrapper-v2.exe

IF that doesn't help, also set each of those .exe files (EXCEPT stellaris.exe !) to run as the Windows Admin user.

Then the game should run from Steam/our launcher, and enable all the DLCs.