If you were granted access to the Age of Empires IV Content Creator (Beta) via an emailed Steam Key, then you should not encounter any issue switching back to the LIVE branch. Simply select "NONE" from the dropdown on the BETAS tab in Steam (steps 1-3 below).
If you launched the Content Creator by using the EssenceEditor.EXE file directly, however, you will need to take additional steps:
- Right-click on the game in your Steam Library and select Properties
- Go to the BETAS tab and select "NONE" from the dropdown
- Close the Steam popup
- Open a navigation folder
- Go to Documents/My Games/Age of Empires IV
- DO NOT go to the Age of Empires IV - Test folder
- Delete the "mods" folder
- Close the navigation folder and re-launch the game
If these steps do not resolve the issue for you, please reach out to Customer Support.