Microsoft Teams, Outlook Crash on ARM After August Updates

Key Takeaways

• Microsoft has confirmed an issue causing Teams and the new Outlook to crash or fail to launch on ARM-based Windows PCs.
• The problem stems from security updates released on or after August 11, 2026, specifically the KB5121003 update.
• Only modern, Store-delivered versions of Teams and Outlook are affected; classic Office applications are not impacted.
• A temporary workaround involves updating the Auto Super Resolution Package via the Microsoft Store to version 1.0.19.0 or later.
• Microsoft has marked the issue as “Mitigated” and is developing a permanent fix.

Microsoft Teams and Outlook Face Launch Issues on ARM Devices Post-Update

Microsoft has acknowledged a significant problem affecting users of ARM-based Windows PCs, where Microsoft Teams and the redesigned Outlook for Windows are experiencing crashes or failing to launch entirely. This disruption follows the installation of security updates deployed on or after August 11, 2026.

August 2026 Patch Tuesday Identified as Root Cause

The core of the problem has been traced back to the KB5121003 update, which was part of Microsoft’s August 2026 Patch Tuesday release. This issue specifically impacts devices running Windows on ARM processors, including newer models such as the Surface Pro 11 and Surface Laptop 7. Microsoft formally confirmed the issue via an advisory posted to its Windows release health dashboard on September 1, 2026, at 19:20 PT.

Affected users may encounter situations where Teams and the new Outlook either refuse to open or unexpectedly terminate shortly after launch. Interestingly, traditional versions of Outlook, Word, Excel, and other components of the Microsoft 365 suite remain unaffected. This distinction suggests the fault lies within the modern packaged app model used by applications delivered through the Microsoft Store, rather than a fundamental flaw in the underlying Office platform.

Impact and Technical Observations

Microsoft indicates that the issue is most prevalent on newly provisioned or freshly imaged PCs that have not yet received recent updates from the Microsoft Store. This suggests a dependency conflict introduced by the security patch, rather than an inherent defect within the applications themselves. Community forums, including Microsoft’s Q&A and Tech Community boards, began reporting these crashes as early as mid-August. Logs from these incidents frequently pointed to AppX and MSIX packaging errors, with one notable error code being 0x80073CFC during the token generation process for the Outlook package.

The affected operating system versions encompass Windows 11 version 24H2, 25H2, and the newer 26H1 release, all of which require specific ARM-based silicon like Qualcomm’s Snapdragon X2 chips. Server platforms are not impacted by this particular issue.

Temporary Workaround Available

While Microsoft has not yet disclosed the precise technical root cause, a temporary workaround has been published. Users experiencing these crashes are advised to open the Microsoft Store, navigate to the Downloads section, select “Check for updates,” and then install the latest version of the Auto Super Resolution Package. Specifically, version 1.0.19.0 or later is required. This package, typically associated with AI-driven upscaling for gaming on Copilot+ PCs, has an unexpected connection to the stability of Outlook and Teams in this scenario.

Microsoft has updated the issue’s status to “Mitigated” on its release health dashboard, indicating that the provided workaround effectively addresses the immediate disruption. The company has stated it is actively working on a permanent resolution, which will be delivered via a future Windows update, with further details to be provided when available.

What You Should Do

• For Affected Users: Open the Microsoft Store, go to “Downloads,” click “Check for updates,” and install the Auto Super Resolution Package version 1.0.19.0 or later.
• For Enterprise IT Administrators: Prioritize verification of Microsoft Store updates, especially on new or freshly imaged ARM-based devices, before deploying new security patches to ensure all packaged app dependencies are synchronized.
• Stay Updated: Monitor the Microsoft Windows release health dashboard for further announcements regarding a permanent fix.

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