Windows 11’s August update broke Teams and Outlook on Arm PCs

It’s been nearly a month since Microsoft released its Patch Tuesday update for Windows 11—known as KB5121003—but problems are still cropping up and being reported by users. The latest issue affects Arm-based computers like the Surface Laptop 7 and Surface Pro 11.

According to a recent Windows health update (spotted by BleepingComputer), Microsoft acknowledges that “Microsoft Teams and Outlook might fail to launch on Arm-based devices.” That’s referring to the new Outlook app, not the classic Outlook app. In fact, classic versions of Microsoft’s apps seem unaffected by the issue at hand:

After installing Windows security updates released on or after August 11, 2026, (KB5121003), Microsoft Teams and the new Outlook for Windows might fail to launch or might close unexpectedly on Arm-based devices, such as Surface Pro 11 and Surface Laptop 7. Classic Outlook, Word, Excel, and other applications are not known to be affected. This issue is most likely to occur on new or freshly imaged PCs that have not yet installed any Microsoft Store updates.

Microsoft says the issue affects Windows 11 versions 24H2, 25H2, and 26H1, and that the company is working on a fix that will be made available with a future Windows update.

For now, if you’ve installed the KB5121003 update and you’re experiencing instability with Microsoft Teams and new Outlook, Microsoft’s provided workaround is to open the Microsoft Store, select Downloads → Check for updates, then install the latest update for the Auto Super Resolution Package (version 1.0.19.0 or later).

This problem is just one more in a long line that traces back to the August Patch Tuesday update. In recent weeks, users have also reported that the update breaks printers and PDFs on Windows 11 and crashing games and causing other PC instability issues.