almost 2 years ago - MrFreake_PDX - Direct link
Right-click Stellaris, go to Properties, Betas tab, it should say "None". If it doesn't, this was your problem.

Otherwise, you can go to Properties, Local Files and Verify Game Files, and that should reaquire the latest version from Steam.

If *that* doesn't work, right-click Stellaris, go to Manage, and Uninstall the game and then reinstall the game.