Microsoft has recently addressed a significant bug that hindered the launch of Teams and Outlook following updates rolled out since the August 2026 Patch Tuesday. This issue predominantly impacted users operating ARM-based Windows devices, such as the Surface Pro 11 and Surface Laptop 7, who had not yet installed the necessary updates from the Microsoft Store while running Windows 11 24H2 or later.
In a detailed Windows release health update, Microsoft clarified, “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.” Notably, classic versions of Outlook, Word, Excel, and other applications were not reported to be affected. The problem was particularly prevalent on newly set up or freshly imaged PCs lacking Microsoft Store updates.
While the exact cause of the issue remains undisclosed, Microsoft has recommended a temporary workaround for affected users: updating the Auto Super Resolution Package. This package enhances the performance of Copilot+ PCs, enabling smoother gameplay experiences.
Fixed by Patch Tuesday cumulative updates
On the evening of September 8, 2026, Microsoft announced that the bug had been resolved through the cumulative updates released as part of the September 2026 Patch Tuesday, specifically in KB5124012. The company urged users to update their devices, stating, “This issue was resolved by Windows updates released September 8, 2026 (KB5124012), and updates released after that date.” They emphasized the importance of installing the latest updates, which include crucial improvements and resolutions to various issues.
This resolution comes amid a series of other known issues linked to Windows updates from August. For instance, on August 24, Microsoft acknowledged that updates to the .NET Framework were disrupting printing and PDF exporting in applications utilizing the Windows Presentation Foundation (WPF) UI framework. Shortly thereafter, they began deploying a fix for a separate bug that arose from peripherals with built-in RGB lighting, which caused gaming problems and system crashes marked by “EXCEPTIONACCESSVIOLATION” errors on Windows 11 systems.
Additionally, Microsoft has advised users to disregard alerts indicating that Microsoft Defender Antivirus has been disabled following last month’s updates. This week, they also resolved known issues that resulted in the loss of custom mouse settings and Windows desktop configurations on certain Windows 11 systems after the installation of the KB5120998 August 2026 preview update.
