The KB5074109 update for Windows 11, released on January 13, 2026, has caused Outlook to freeze and hang for users with POP account profiles, preventing the application from exiting properly. Microsoft is currently investigating this emerging issue, which has not yet been listed in the Known Issues section of the update's release notes. A temporary workaround suggested involves uninstalling the KB5074109 update, though this may expose systems to security vulnerabilities.