Microsoft has issued an unusual public advisory asking users to uninstall the Windows 11 January 2026 security update after widespread reports of serious system and application problems.
The update, identified as KB5074109, began rolling out automatically on January 13 and upgrades affected systems to OS Build 26200.7623 or similar versions. Since its release, users have reported issues ranging from Outlook Classic freezing to black screens and application crashes.
The most severe problems have been reported by users of Outlook Classic, particularly those using POP email accounts or local PST files. The issues appear most common when PST files are stored in cloud-synced folders such as OneDrive.
Affected users say Outlook may freeze, show a “Not Responding” message, fail to close properly, or repeatedly redownload emails. In many cases, the app becomes unusable. Microsoft’s current guidance advises switching to Outlook webmail or uninstalling the update until a permanent fix is released.
The problems linked to KB5074109 extend beyond Outlook. Users have also reported black screens, reset desktop settings, broken File Explorer customizations, and apps freezing when attempting to access cloud storage services like OneDrive or Dropbox.
The scale of the issues has led many users to treat uninstalling the update as a temporary workaround while Microsoft works on a full fix.
Microsoft has published a support document outlining several temporary solutions. These include using webmail instead of the Outlook desktop app and moving PST files out of cloud-synced folders.
If those steps fail, users can remove the update by navigating to Settings, then Windows Update, Update history, and selecting Uninstall updates. However, Microsoft has cautioned that rolling back the January update could expose systems to security risks, as the patch included more than 100 security fixes.
Microsoft has already released out-of-band updates to address other serious bugs from this update cycle, including issues affecting Remote Desktop logins and system shutdowns. The Outlook Classic problem, however, remains unresolved.
The company said it is still investigating the root cause and plans to deliver a broader fix in a future update. For now, the incident represents a difficult start to Windows 11’s update cycle for 2026, following a 2025 marked by multiple disruptive patches.
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