According to internal Microsoft investigations under tracking number TM1466820, users launching the Teams desktop client on Windows face startup delays lasting up to two minutes. The company recommends using web versions or mobile applications to maintain productivity while investigations continue.
Windows ARM Start Failures Linked to Security Update KB5121003
Modern ARM-based hardware models, including the Surface Laptop 7 and Surface Pro 11 running operating system versions 24H2, 25H2, or 26H1, experience severe start failures in Teams and the new Outlook version. According to Microsoft, these disruptions stem from the security update KB5121003 released on August 11, 2026. Internal company analyses confirm that classic applications like Word, Excel, and traditional Outlook remain unaffected by this specific glitch. To mitigate the ARM architecture issue, Microsoft issued a concrete workaround instructing users to update the “Auto Super Resolution Package” to version 1.0.19.0 or higher through the Microsoft Store.
MacOS Call Disruptions and Exchange Online Email Delays
Apple device users face separate hurdles as platform-specific bugs disrupt daily collaboration. On September 4, 2026, Microsoft logged issue TM1466659, which blocks MacOS users from joining active calls and meetings. Simultaneously, cloud infrastructure instability creates delays in sending and receiving emails involving external senders via Exchange Online, according to Microsoft status disclosures from September 4, 2026. Administrators monitoring these events must rely on the Microsoft 365 Admin Center for real-time telemetry and resolution tracking.
Pro Tip: IT managers dealing with ARM startup failures on Surface devices should check the Microsoft Store immediately for the Auto Super Resolution Package update version 1.0.19.0 to bypass application launch blocks.
Frequently Asked Questions
Which devices are affected by the Microsoft security update KB5121003?
According to Microsoft, ARM-based systems running operating system versions 24H2, 25H2, or 26H1—specifically the Surface Laptop 7 and Surface Pro 11—experience startup failures with Teams and the new Outlook.
How can users fix Microsoft Teams startup delays on standard Windows PCs?
Microsoft advises affected users to temporarily switch to the web version of Teams or utilize mobile applications while engineers investigate the root cause tracked under identifier TM1466820.
What is causing meeting connection failures on Apple devices?
Microsoft identified an issue tracked as TM1466659 on September 4, 2026, which specifically prevents MacOS users from joining active calls and meetings.
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