Microsoft fixes Teams, Outlook launch failures on ARM Windows PCs

Microsoft has fixed a bug that prevented Teams and the new Outlook for Windows from launching after updates released since the August 2026 Patch Tuesday. The issue affected users who had not installed Microsoft Store updates on ARM-based devices such as Surface Pro 11 and Surface Laptop 7 running Windows 11 24H2 or later.

Microsoft said the problem could occur after security updates released on or after August 11, 2026, including KB5121003. Teams and the new Outlook might fail to launch or close unexpectedly. Classic Outlook, Word, Excel, and other applications were not known to be affected. The problem was most likely on new or freshly imaged PCs without Microsoft Store updates.

As a temporary workaround, Microsoft advised updating the Auto Super Resolution Package, which enables Copilot+ PCs to use AI to make gameplay smoother. Microsoft has not disclosed the root cause.

Updates released on September 8, 2026, including KB5124012, resolved the issue. Microsoft asked users to install the latest update. The fix follows other August problems, including .NET Framework updates breaking printing and PDF exporting in Windows Presentation Foundation (WPF) apps and the KB5120998 preview update wiping custom mouse and desktop settings on some Windows 11 systems.