Final answer:
To best meet the goal of reducing risks with OS updates, implement a multi-layered security approach including robust testing, phased rollouts, regular backups, secure software sources, controlled access, and staff training for improved password practices and two-factor authentication.
Step-by-step explanation:
To reduce risks associated with updating critical operating systems, security experts should ensure a robust testing process before deployment, employ phased rollouts to catch issues early, and maintain regular backups to recover from any unforeseen problems. Ensuring that software is always sourced from trustworthy repositories and maintaining a tight control on access to these operating systems through user permissions are also crucial steps. Beyond the technical measures, it's equally important to foster a culture of security which includes regular security training for all staff and the implementation of stronger passwords and two-factor authentication to protect against unauthorized access.