Microsoft is addressing an issue with the classic Outlook desktop client freezing and hanging, particularly for users with POP email accounts, following the January security update KB5074109 for Windows 11 versions 25H2 and 24H2. The problem causes Outlook to fail to exit properly and not restart after being closed. Microsoft is investigating the issue but has not provided a timeline for a resolution. Users can temporarily resolve the issue by uninstalling the KB5074109 update through the Settings app, although this may expose their devices to security vulnerabilities.