Microsoft has issued an unusual public advisory telling users to uninstall the Windows 11 January 2026 security update (KB5074109) after widespread reports that it is causing serious system and application issues. The update, which began rolling out automatically on January 13 and advances affected systems to OS Build 26200.7623 or similar releases, has been linked to problems including Outlook Classic freezing, black screens, and app crashes.
The hardest hit appear to be users of Outlook Classic who rely on POP email accounts or local PST files, particularly those stored in cloud folders such as OneDrive. For these users, Outlook may hang, show as “Not Responding,” fail to close properly, or repeatedly redownload messages, making the app effectively unusable. Microsoft’s official guidance now recommends either switching to Outlook webmail or uninstalling the problematic update until a permanent fix is available.
What’s Going Wrong and How to Fix It
The problems caused by KB5074109 aren’t limited to Outlook. Many users say the update has triggered a range of other issues, including black screens on some systems, reset desktop settings, broken File Explorer customizations, and apps freezing when trying to access cloud storage services like OneDrive or Dropbox. The bugs have been widespread enough that uninstalling the update is now being seen as a reasonable temporary fix while Microsoft works on a proper solution.
In response, Microsoft has published a support document outlining a few workarounds. These include switching to webmail instead of using the Outlook desktop app and moving PST files out of cloud-synced folders. If those steps don’t help, users can also roll back the update entirely by going to Settings > Windows Update > Update history > Uninstall updates. However, Microsoft has previously warned that removing the patch could expose systems to security risks, since the January update included more than 100 security fixes.
Microsoft has already released out-of-band updates to fix other serious bugs from this update cycle, such as issues with Remote Desktop logins and system shutdowns. The Outlook problem, however, remains unresolved. The company says it’s still investigating the root cause and plans to ship a broader fix in a future update. For now, this marks a rocky start to Windows 11’s update schedule for 2026, following a 2025 that was already plagued by several disruptive patches