Microsoft 365 Alert – Service Degradation – Microsoft Teams – Users may not be presented a microphone option to mute or unmute in Microsoft Teams meeting breakout rooms – RESOLVED

11/08/2025 08:38:00 AM

NHSmail Reference: INC46600510

Microsoft Reference: TM1130939

Issue Status: RESOLVED

Issue Description: Users may not be presented a microphone option to mute or unmute in Microsoft Teams meeting breakout rooms.

More info: Impact is specific to breakout room attendees. Meeting organizers are not impacted.

While Microsoft are focused on remediation, their testing indicates users may be able to avoid impact by utilizing Microsoft Teams on the web as opposed to the Microsoft Teams desktop client.

Final Update: 15/08/2025 08:25:00 AM – Microsoft have validated that their deployment has completed for the affected environment, and they have confirmed users are now presented with a microphone option to mute in Microsoft Teams breakout rooms as expected.

Scope of impact: Any user in Microsoft Teams meeting breakout rooms may be impacted.

Root cause: A recent service update, designed to change the way that the mute state is communicated to the service, is causing impact.

Next update by: Microsoft are analyzing the offending service update to understand why the potential for impact wasn’t caught during the update testing and validation phase. These actions will help us to clarify what actions they can take to ensure similar impact doesn’t occur in future and to continue our ongoing mission to improve the resilience of our service for all Microsoft Teams users