Microsoft has confirmed that its August 2026 security update is preventing the new Outlook and Teams apps from launching reliably on Arm-based Windows devices, including Surface Pro 11 and Surface Laptop 7. The company acknowledged the fault on 1 September and added it to its Windows release health dashboard, noting it primarily affects new or freshly imaged PCs that haven't yet received Microsoft Store updates, while classic Outlook, Word and Excel remain unaffected.

The problem stems from security updates released on or after 11 August (KB5121003) and also hits Windows 11 26H1 on compatible Snapdragon X2 hardware. Microsoft hasn't identified the root cause but suggests installing version 1.0.19.0 or later of the Auto Super Resolution Package, an AI gaming tool, as a workaround. Separately, an August 27 preview update has caused custom mouse cursors to reset to Windows defaults on non-English installations of Windows 11 24H2 and 25H2, with Microsoft saying the settings cannot currently be restored manually.