Teams Room (Yealink) spontaneously muting mics repeatedly in some meetings

Hi @Kim Ahmad,

Welcome to the Microsoft Q&A forum.

I would like to provide you with the following information:

I understand that when users join a Microsoft Teams meeting, the microphone is automatically muted by default.

This issue occurs when you use the Yealink VCM36-W device during the meeting. However, when you attempted to reproduce the issue, it did not occur again.

In this case, I recommend that you contact Microsoft Technical Support. They have specialized tools to perform a deeper investigation in order to determine whether the issue is caused by settings or policies configured in Microsoft Teams, or by the device itself.

Please follow the steps below to contact Microsoft Technical Support.

Note: The following steps require administrator (Admin) permissions for the tenant. If your account does not have admin privileges, please contact your IT department for assistance with these steps.

Step 1: Go to admin.microsoft.com

Step 2: Select Help & Support

Step 3: Enter the subject: Request support to investigate Microsoft Teams

Step 4: Select Contact Support

Step 5: Choose your preferred contact method

After the system receives the ticket and assigns it to an agent, the agent will proactively contact you to assist with further investigation and resolution.

 I hope this information is helpful. Please follow these steps and let me know if it works for you. If not, we can work together to resolve this.   

Thank you for your patience and your understanding. If you have any questions or need further assistance, please feel free to share them in the comments on this post so I can continue to support you.

I look forward to continuing the conversation.

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The room shows 0 health incidents over the last 90 days. We've already updated the firmware on all the Yealink devices, and reseated their connections, and all the devices are on and using their external power, not USB power. The mics are wireless, and all paired. I don't see anything in the health logs that would indicate that they're dropping out.

The behavior matches a conferencing microphone/speaker health or configuration issue on a Microsoft Teams Rooms (MTR) device rather than a per‑meeting or per‑participant setting.

In Teams Rooms, the audio path is treated as a set of conferencing peripherals. When the configured conferencing microphone or speaker becomes unavailable, unstable, or is seen as a non‑viable device, Teams Rooms can switch devices and raise alerts. With Yealink arrays and an external audio processor in the chain, intermittent connectivity, power, or firmware problems can manifest as the room mics effectively “dropping out” and then coming back, which can look like spontaneous muting.

Use the following checks, focusing on hardware and device configuration rather than meeting options:

1. Verify conferencing mic/speaker health
   • In the Teams Rooms Pro Management portal or Teams admin center, check the room’s device signals for:
     • Conferencing Microphone
     • Conferencing Speaker
     • Configured Conferencing Microphone
     • Configured Conferencing Speaker
     • Configured Default Speaker
   • If any of these show Unhealthy or warnings around the time of the issue, it indicates Teams Rooms is losing or failing over from the configured audio device during meetings.
   • This aligns with scenarios where no viable conferencing microphone is available, or where Teams falls back to a non‑viable device (for example, small internal speakers or onboard jacks), which is explicitly called out as a cause for audio alerts.
2. Check power and cabling for all audio peripherals
   • Ensure the Yealink audio processor and any USB audio interfaces are using their external power supplies and are turned on. Many audio peripherals require more power than USB alone provides.
   • Reseat all USB connections between the MCore and the audio processor/mic receiver. If the issue persists, test with a different USB cable.
   • If USB extenders are in use between the MCore and the audio hardware, verify they are supported for that device and meet length/USB‑spec requirements. Unsupported or marginal extenders can cause intermittent device drops that appear only under load (for example, in larger or longer meetings).
3. Update and validate firmware on Yealink audio devices
   • If any of the Yealink mics, receivers, or audio processors were recently updated, confirm the firmware update completed successfully. A partially applied update can leave a device in an unusable or unstable state.
   • Power‑cycle the affected audio devices (not just the MCore) to clear any stuck state.
   • Confirm with Yealink that all audio components (VCM36‑W, processor, etc.) are on current, supported firmware and that there are no known issues with Teams Rooms muting or device resets on those versions.
4. Eliminate non‑viable or fallback audio devices
   • On the Teams Rooms device, ensure the configured Conferencing Microphone and Conferencing Speaker are explicitly set to the Yealink audio chain, not to built‑in console speakers, HDMI display speakers, or headset jacks.
   • Because Teams Rooms filters out non‑viable devices, if the system is forced to use such a device (for example, HDMI audio from a front‑of‑room display that sleeps), it can trigger unhealthy audio signals and unstable behavior.
   • If the app is configured to use HDMI display speakers, be aware that HDMI audio disconnects when the display sleeps; this is specifically called out as a misconfiguration scenario that generates alerts.
5. Correlate with specific meetings and room usage
   • For meetings where the issue occurs repeatedly, compare the device health timeline in the Teams Rooms Pro Management portal with the meeting times. Look for repeated transitions of the conferencing microphone or speaker between Healthy/Unhealthy.
   • If the pattern aligns with room usage (for example, longer meetings, meetings where the display sleeps/wakes, or where HDMI ingest is used), it further points to hardware/power/connection or HDMI‑audio configuration rather than a meeting policy.
6. If problems persist
   • After verifying power, cabling, firmware, and configured devices, and confirming that no non‑viable devices are being used, engage Yealink support with logs from the Teams Rooms device and the Pro Management portal. Provide timestamps of meetings where the mics muted themselves and note any Unhealthy signals for conferencing audio devices.

There is no meeting‑level or participant‑level Teams setting in the provided material that would selectively mute a room’s physical microphones in the way described. The documented causes and resolutions focus on the health and configuration of conferencing microphones and speakers, power, cabling, firmware, and the use of viable audio devices in Teams Rooms.

References:

• The microphone or speaker status is Unhealthy
• Best practices for hosting hybrid meetings and events in Microsoft Teams Rooms