Description: Microsoft confirmed that an August 2026 Windows update could stop Teams and new Outlook from opening on ARM-based Surface PCs. Find the affected versions, the correct September fix and the Microsoft Store workaround.
If Teams and the new Outlook stopped launching on your ARM-based Surface after a Windows update, check the Windows build before reinstalling either app. Microsoft confirmed this issue after its August 11, 2026 security updates. It was resolved on September 8: KB5124008 for Windows 11 24H2/25H2 and KB5124012 for 26H1.[1][2]
Does your PC match the reported problem?
Microsoft names ARM-based Surface Pro 11 and Surface Laptop 7 as examples. Newly purchased or freshly reimaged PCs that have not yet received Microsoft Store updates are especially likely to encounter it. The affected apps are Microsoft Teams and the new Outlook for Windows. They may fail to open or close unexpectedly. Classic Outlook, Word and Excel are not known to be affected by this specific issue.[1]
Check the processor rather than relying on the Surface name alone. An Intel- or AMD-based PC with the same symptom needs its own diagnosis. Microsoft has not published a full technical root-cause explanation connecting the Windows update to the Store package.
Which KB applies to your Windows version?
| Windows 11 | August update associated with the issue | September 8 fix |
|---|---|---|
| 24H2 | KB5121003 | KB5124008 |
| 25H2 | KB5121003 | KB5124008 |
| 26H1 | KB5121000 | KB5124012 |
The different number for 26H1 matters: searching for KB5121003 on a 26H1 machine may lead you down the wrong path.[1][2]
Safe checks and the fix
- Open Settings → System → About and check whether the processor is ARM-based.
- Press Win + R, enter winver, and note the Windows 11 version.
- Open Settings → Windows Update → Update history and look for the appropriate September fix or a later cumulative update.
- Record whether Teams, new Outlook, or both fail, and whether the app closes immediately. Send the details to IT on a work-managed PC.
- Install the latest Windows update offered for your device and restart. Microsoft's release-health records mark the issue Resolved as of September 8, 2026.[1][2]
If your organization has not yet deployed the Windows fix, Microsoft documents a temporary workaround: open Microsoft Store → Downloads → Check for updates and update the Auto Super Resolution Package to version 1.0.19.0 or later.[3] The package sounds graphics-related, but Microsoft specifically recommended it. The exact technical mechanism was not disclosed. Browser-based Teams may help with an urgent meeting where company policy permits it; that is a practical alternative, not the official fix.
Still failing after the update?
Check whether the latest Store app updates are installed, then collect the Windows version, app names, error text and time of failure for your support team. Other account or application problems can produce similar symptoms. Avoid removing security updates, deleting mail accounts, resetting Windows or clearing local app data as a first response; unsynced drafts and locally stored files may be at risk.
Bottom line
This particular ARM Windows 11 launch failure is fixed by the September 8 updates and later releases. Match the KB to your version first. The Auto Super Resolution Package update remains a documented fallback for devices still waiting for the Windows fix.
References (4)
[1] Microsoft, Windows 11 24H2 release health (resolved 2026-09-08): https://learn.microsoft.com/en-us/windows/release-health/status-windows-11-24h2
[2] Microsoft, Windows 11 26H1 release health (resolved by KB5124012, 2026-09-08): https://learn.microsoft.com/en-us/windows/release-health/status-windows-11-26h1
[3] Microsoft, KB5121003 release notes and workaround (2026-08-11): https://support.microsoft.com/en-us/servicing/os/windows-11/2026/08/kb5121003-windows-11-24h2-25h2-security-update
Checked October 17, 2026 (JST). This is a documentation-based assessment, not a hands-on reproduction test.
