Since the repair install will remove all Windows Service Packs and security updates that may have been installed on your computer, you cannot rely on Automatic Updates to re-apply Windows Service Packs or updates that the computer is now missing. You will need to manually install Windows Service Packs and updates to protect your computer. Until you do your computer will be unprotected against any vulnerabilities that were previously resolved by Windows Service Packs or security updates.
Further thanks to the Microsoft Windows Update engineering team for clarifying the issues involved in causing AU to fail.
Article ID: 555615 - Last Review: 14 Feb 2017 - Revision: 1