Microsoft has issued an unusual public advisory urging users to uninstall the Windows January 11, 2026 security update (KB5074109) after widespread reports that it is causing serious system and application problems. The update, which rolled out automatically on January 13 and updates affected systems to OS Build 26200.7623 or similar versions, has been linked to issues such as Outlook Classic freezing, black screens and app crashes.
The hardest hit appear to be Outlook Classic users who rely on POP email accounts or local PST files, particularly those stored in cloud folders like OneDrive. These users may experience Outlook hanging, showing as “Unresponsive”, failing to close properly, or repeatedly re-downloading messages, rendering the app virtually unusable. Microsoft’s official guidance now recommends either switching to Outlook webmail or uninstalling the problematic update until a permanent solution is available.
What’s going wrong and how to fix it?
The issues caused by KB5074109 are not limited to Outlook. Many users say the update has triggered a number of other issues, including black screens on some systems, reset desktop settings, incorrect File Explorer customizations, and apps freezing when trying to access cloud storage services like OneDrive or Dropbox. The bugs are so widespread that uninstalling the update is now considered a sensible temporary solution while Microsoft works on a suitable solution.
In response, Microsoft has released a support document that describes some workarounds. These include switching to webmail instead of using the Outlook desktop app and moving PST files from cloud-synced folders. If these steps don’t help, users can also completely roll back the update by going to Settings > Windows Update > Update History > Uninstall Updates. However, Microsoft has previously warned that removing the patch could introduce security risks to systems, as the January update contained more than 100 security fixes.
Microsoft has already released out-of-band updates to fix other serious bugs from this update cycle, such as: B. Issues with remote desktop logins and system shutdowns. However, the Outlook problem remains unresolved. The company says it is still investigating the root cause and plans to provide a more comprehensive fix in a future update. For now, this marks a rocky start to Windows 11’s 2026 update schedule, after 2025 was already plagued by several disruptive patches
