Microsoft 365 Alert – Service Degradation – Microsoft Teams – Some guest users may be unable to unmute their mics in recurring Microsoft Teams meetings when recording is enabled – ONGOING

18/12/2025 09:05:00 AM

NHSmail Reference: INC46708300

Microsoft Reference: TM1198582

Issue Status: ONGOING

Issue Description: Some guest users may be unable to unmute their mics in recurring Microsoft Teams meetings when recording is enabled.

More info: This issue is specific to guest users who have joined Microsoft Teams meetings through the Windows or Mac desktop clients. This issue also impacts guest users when attempting to share their screen or turn on their camera during affected Microsoft Teams meetings. As a workaround, affected guest users can clear their cache to remove expired authentication components or utilize the Microsoft Teams web app or mobile app.

Current Update: 06/01/2025 10:02:00 AM – The process of preparing Microsoft’s fix to address the issue on the Teams desktop client for Mac is progressing as expected. Their estimation for the fix reaching affected users remains early February 2026, and they will continue monitoring this process to ensure it completes as expected by this time.

Scope of impact: Some external guest participants attempting to unmute their microphones, share their screen, or use their camera during recurring Microsoft Teams meetings while recording may be impacted. This information may be updated as our investigation continues.

Root cause: The impact is the result of an issue affecting the authentication components assigned to guest users when joining recurring Microsoft Teams meetings and recording the meeting in which stale components are being leveraged and causing an error to occur that prevents these guest users from unmuting their mics, sharing their screen, or using their camera.

Next update by: Wednesday, January 21, 2026, at 3:30 AM UTC