Bootstrapper error / Couldn't start launcher!

If you're seeing an error like this when you start the launcher your anti virus program has played a role!

What this basically means is that your anti virus program (AV) has flagged the file bootstrapper.exe as a potential virus and quarantined it. To solve this please do the following:

1. Open your AV program and look in the quarantined list (some programs call it virus chest). If the file is there restore it and mark it as safe, then start the game and it should work as normal. 
2. If the file isn't there you need to reinstall the launcher following these steps.
   1. Exit the Steam app entirely
   2. Uninstall Paradox Launcher v2 from the Windows "Apps and features" utility, if still present
   3. Delete the following folders if still present:
      1. C:/users/<UserName>/AppData/Local/Programs/Paradox Interactive/
      2. C:/users/<UserName>/AppData/Local/Paradox Interactive/
      3. 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.
   4. Restart your PC
   5. Open your AV program and add bootstrapper.exe and paradoxlauncher.exe to your safe/approved apps list
   6. Start steam.exe as administrator (right click steam.exe > run as administrator)
   7. Start the game that had the issue