Advisories
Microsoft Resolves Teams/Outlook Launch Failure on ARM Windows PCs
Microsoft has patched a bug that stopped Teams and the new Outlook from starting on ARM‑based Windows devices after the August 2026 Patch Tuesday updates. The issue hit fresh or un‑updated Surface Pro 11 and Surface Laptop 7 units running Windows 11 24H2 and later. A temporary fix was to install the Auto Super Resolution Package, but the final resolution came with the September 8, 2026 cumulative update (KB5124012). The company also addressed other August‑update glitches, from WPF printing errors to RGB‑lighting induced crashes.
In a recent Windows release health update, Microsoft confirmed that a flaw in the August 2026 Patch Tuesday updates had caused Microsoft Teams and the new Outlook app to fail on ARM‑based Windows PCs. The problem surfaced on devices that hadn’t yet received any Microsoft Store updates, most notably the Surface Pro 11 and Surface Laptop 7 running Windows 11 24H2 or newer.
What went wrong?
After installing the security updates released on or after August 11 2026 (KB5121003), users found that launching Teams or Outlook would either not start or crash immediately. Classic Office apps, Word, Excel, and the older Outlook version were unaffected. The issue was most common on newly provisioned or freshly imaged machines that had not yet pulled any Microsoft Store updates.
Microsoft’s interim workaround
While a full fix was pending, Microsoft advised affected customers to install the Auto Super Resolution Package, which enables AI‑enhanced gameplay on Copilot+ PCs. This update provided a temporary stopgap, allowing Teams and Outlook to launch again on most affected devices.
Patch Tuesday delivers the fix
On September 8 2026, Microsoft rolled out the cumulative update KB5124012. The release notes state that the Teams/Outlook launch bug is now resolved and recommends that all users install the latest update to receive the fix along with other improvements.
Other August‑update side effects
- WPF‑based apps lost printing and PDF export functionality due to .NET Framework changes.
- RGB‑lighting peripherals caused EXCEPTION_ACCESS_VIOLATION crashes on some Windows 11 systems.
- The KB5120998 preview update wiped custom mouse and desktop settings on certain machines.
- Microsoft Defender Antivirus falsely reported being disabled after the August updates.
Microsoft urges users to keep their systems fully updated, especially on ARM devices, to avoid similar disruptions in the future.
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