GoKawiilMicrosoft resolves ARM Windows bug crashing Teams and Outlook via September patch
Microsoft has patched a bug that stopped Teams and the new Outlook for Windows from launching on ARM-based devices like the Surface Pro 11 and Surface Laptop 7. The issue, triggered by August 2026 security updates (KB5121003), mainly hit new or freshly imaged PCs without Microsoft Store updates. The fix arrived with the September 8 cumulative update, KB5124012.
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This marks another instance of Patch Tuesday updates breaking core productivity apps, following a separate August bug that broke printing and PDF exports in WPF-based apps. For enterprises relying on ARM Copilot+ PCs, repeated update-induced outages in essential tools like Teams and Outlook raise concerns about Microsoft's update testing process.
- Bug affected Teams and new Outlook on ARM Windows 11 24H2+ devices after August updates.
- Microsoft fixed it via the September 8, 2026 cumulative update KB5124012.
- It's part of a pattern of recent Windows update issues, including a separate WPF printing bug from August.
Microsoft Surface Laptop 7 Copilot+ PC — The ARM-based Surface Laptop 7 is exactly the Copilot+ machine at the center of this Teams and Outlook hiccup, and now that Microsoft has patched it, the experience is back to smooth. It's a thin, quiet Snapdragon-powered Windows 11 laptop with on-device AI features and long battery life for everyday work.
See Microsoft Surface Laptop 7 Copilot+ PC on Amazon → Affiliate link — we may earn a commission on purchases, at no extra cost to you. Product picked by AI based on this article; it is not a tested recommendation.Source: bleepingcomputer.com, 2026-09-11
Published there as: “Microsoft fixes Teams, Outlook launch failures on ARM Windows PCs”
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