Microsoft Teams and Outlook Fail to Launch on ARM-based Windows PCs After August 2026 Updates

Launch Failures on ARM-based Windows Devices

Microsoft has acknowledged a known issue causing Microsoft Teams and New Outlook to fail to launch or close unexpectedly on ARM-based Windows devices. This problem specifically impacts devices like the Surface Laptop 7 and Surface Pro 11 running Windows 11 24H2 or newer, following the installation of security updates released on or after August 11, 2026 (KB5121003).

Affected Applications and Conditions

The issue is confined to Microsoft Teams and the New Outlook for Windows, with Classic Outlook, Word, Excel, and other applications remaining unaffected. It is most prevalent on new or freshly imaged PCs that have not yet received Microsoft Store updates, suggesting a dependency on updated components for these applications to function correctly post-Windows update.

Temporary Workaround Provided

While Microsoft has not disclosed the root cause, it has provided a temporary workaround. Affected users are advised to update the Auto Super Resolution Package to version 1.0.19.0 or later through the Microsoft Store. This package is typically associated with Copilot+ PCs for AI-enhanced game performance, but its update appears to mitigate the Teams and Outlook launch failures.

Ongoing Fix and Broader Update Issues

Microsoft is currently developing a permanent fix, which will be delivered in a future Windows update. This incident is part of a series of known issues stemming from August's Windows updates, including problems with printing and PDF export after .NET Framework updates, and system crashes on Windows 11 devices related to RGB lighting peripherals.