Microsoft rushes out second emergency Windows update to fix Outlook crash bug

Windows 11

• Microsoft releases urgent Windows 11 update to fix Outlook crashes with cloud files
• Latest patch is cumulative and includes previous January 2026 emergency fixes
• Install the update promptly to restore Outlook and cloud file stability.

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Microsoft has released another out-of-band update for Windows 11 to address a critical bug that caused Outlook to crash or become unusable for some users. The emergency patch fixes issues introduced by the company’s January 2026 security update, particularly affecting apps that interact with files stored in cloud-backed locations such as OneDrive.

According to Microsoft, the bug caused certain applications that “open or save files stored in cloud-backed locations” to stop responding or throw error messages. Outlook was among the hardest hit, especially for users who store PST files in cloud-synced folders. In some cases, Outlook would crash repeatedly, refuse to open, or hang indefinitely, effectively breaking email access for affected systems.

This marks the second out-of-band update Microsoft has had to issue this year to deal with fallout from the January 2026 Patch Tuesday release. Just last week, the company pushed an emergency fix for separate issues that prevented some Windows 11 devices from shutting down or entering hibernation, while other systems running Windows 10 and Windows 11 were unable to log in using Remote Desktop.

Out-of-band updates are relatively rare and are typically reserved for serious problems that cannot wait for Microsoft’s regular monthly update cycle. The fact that Microsoft has now issued two such patches in quick succession underlines how disruptive the January update cycle has been.

The good news for users is that the latest fix is cumulative. That means installing this update should also include previous emergency fixes related to the January security release, without the need to install multiple patches separately. Microsoft recommends that affected users apply the update as soon as possible to restore normal Outlook behaviour and avoid further instability when working with cloud-stored files.

The rocky start to Windows updates in 2026 follows a turbulent 2025, which also saw several high-profile patch-related bugs affecting core Windows features. While Microsoft continues to emphasise the importance of timely security updates, the repeated need for emergency fixes is likely to raise fresh concerns among IT administrators and everyday users alike about update reliability.

Users who rely on Outlook with cloud-based PST files should see improvements after installing the latest out-of-band update. Microsoft has not indicated whether further fixes will be required, but says it will continue monitoring feedback closely.