Microsoft is investigating a bug—tracked as incident TM1466820—that’s causing the Microsoft Teams desktop app to fail or stall during startup on certain Windows systems. Users report either the client never launches or it takes up to two minutes to become responsive. The issue only surfaces during the app’s first launch under affected conditions.
The impact seems patchy: it affects “some users” within organizations, especially those opening Teams to check new messages. But not every user or tenant is seeing delays. The variance suggests factors like machine configuration, user profile, or local setup may be playing a role.
What We Know & What You Can Do
So far, Microsoft’s deep dive into service logs and telemetry hasn’t surfaced a smoking gun. Engineers are now reaching out to impacted customers to gather client-side logs in hopes of pinpointing the trigger. Meanwhile, Microsoft hasn’t given a fix date.
Until then, there are workarounds: use Teams in a web browser or switch to the mobile app. These options seem spared by the issue and allow users to stay productive. IT teams are also advised to keep tabs on the Microsoft 365 admin center’s service health dashboard for updates and wide notification to staff ahead of a broader disruption.
What’s Behind It & Why It Matters
This isn’t Microsoft’s first rodeo with Teams startup glitches. Earlier in 2026, the build-caching system in the Teams client introduced launch failures; that was resolved by rolling back a service update. Additionally, Windows 11 devices powered by ARM CPUs—including certain Surface Pro and Surface Laptop models—suffered similar issues tied to a security update, which Microsoft mitigated via the Microsoft Store.
Teams has become core in hybrid work setups. Even a two-minute delay can cascade into missed meeting starts, frustrated users, and lower confidence in IT operations. Because many organizations are using Teams daily, consistency and reliability are non-negotiable. This issue underscores the fragility of depending heavily on desktop client performance.
Microsoft hasn’t committed to a resolution timeline. But the shift toward gathering local logs reflects a move from broad surface-level triage toward diagnosing specific environmental triggers. Organizations with many Windows clients should expect more detailed guidance or a patch ahead. In the meantime, using the web or mobile versions isn’t ideal—but it’s a viable stopgap.
