💡 Our Technical Review in summary
- Microsoft has officially canceled the previously announced plan to rename or introduce a separate executable (
ms-teams_modulehost.exe) for Teams Calling and Meetings on Windows. - The proposed change was originally intended as a workaround for a Windows compatibility issue. However, Microsoft has since resolved the underlying issue directly within the Windows operating system.
- The fix is now integrated into Windows versions 24H2 and 25H2 via update KB5068861, making the Teams-level executable change unnecessary.
#### Impact
- General Organizations: There is no impact on organizations that do not participate in the Microsoft Technology Adoption Program (TAP). The Teams client will continue to operate using its standard process architecture.
- TAP Participants: Organizations in the “earlyadopter” subset (Ring 1.5) who saw this change will see it fully rolled back. No lasting configuration changes or behavioral issues will remain on client machines.
- Performance and Compatibility: There is no risk of service disruption or feature degradation. If the required Windows KBs (KB5068861) are not yet installed in your environment, specific new features depending on them will simply remain disabled rather than causing functionality to break.
- Technical Infrastructure: The requirement to allowlist a new binary or configure separate Quality of Service (QoS) settings for
ms-teams_modulehost.exehas been retracted.
#### Action Required
- No Administrative Action Needed: Microsoft has confirmed that no changes to tenant configuration or admin settings are required.
- Update Internal Documentation: If your IT team had already prepared documentation, firewall allowlists, or QoS policies for the
ms-teams_modulehost.exebinary, these preparations can be discarded or reverted. - Windows Updates: While not strictly required for current Teams stability, it is recommended to continue standard deployment of Windows cumulative updates (specifically KB5068861 for 24H2/25H2) to ensure future features function as intended.
Microsoft Official Update
Service: N/A
Category: planForChange
Severity: normal
Updated January 15, 2026: We are canceling a proposed change related to renaming the existing Calling and Meetings executable.
No action is required from administrators. This change did not introduce a new binary. It involved renaming the existing executable used for Calling and Meetings as a workaround for a Windows compatibility issue.
What Happened?
To reduce administrative effort, we partnered with the Windows team to deliver the fix for a Windows compatibility issue. With the Windows fix now fully rolled out in Windows 24H2 and 25H2, the executable name change is no longer required and has been rolled back.
Was this a security, reliability, or compliance issue?
- This was not a security or compliance issue.
- It was a platform compatibility issue in Windows.
- No customer data, identity, or tenant configuration was at risk.
Was my tenant impacted?
Only organizations participating in our Technology Adoption Program (TAP) were affected. Specifically, the change applied only to the TAP Admin earlyadopter subset (Ring 1.5).
If your organization does not participate in the Microsoft Technology Adoption Program, you were not impacted in any way. The change has been fully rolled back for TAP participants, with no lasting configuration or behavioral changes on client machines. No administrator action is required.
What if we haven’t deployed recent Windows updates yet?
We understand that many enterprises deploy Windows cumulative updates on managed timelines.
- There is no risk or degradation if the referenced Windows KBs are not installed.
- New features that depend on these Windows updates will explicitly check for the presence of the required KBs and will only enable when they are available.
- If the KBs are not installed, those features simply remain disabled—no functionality breaks and no admin action is required.
Windows updates that include the fix
The Windows compatibility fix is included in Windows updates for versions 24H2 and 25H2, delivered through KB5068861.
What to expect next?
- No changes to admin configuration or tenant settings
- No service disruption
—Original message—
[Introduction]
We’re improving the performance and startup time of calling features in the Microsoft Teams Desktop Client for Windows. To achieve this, we’re introducing a new child process named ms-teams_modulehost.exe that will handle the calling stack separately from the main application process (ms-teams.exe). This change optimizes resource usage and enhances meeting experiences.
[When this will happen:]
Rollout will begin early January 2026 and complete by late January 2026.
Note: Timelines may shift due to year-end feature flag rollout freeze.
[How this affects your organization:]
- Who is affected: All users running the Teams Desktop Client on Windows.
- What will happen:
- A new process (ms-teams_modulehost.exe) will appear in Task Manager under the main Teams process (ms-teams.exe).
- This process is dedicated to calling features and improves performance.
- No changes to user workflows or UI; however, admins should ensure endpoint and security software allow this new process.
[What you can do to prepare:]
- Update endpoint management and security software to allowlist ms-teams_modulehost.exe alongside ms-teams.exe.
- Communicate this change to helpdesk staff to avoid confusion during troubleshooting.
- Update internal documentation if you reference Teams process names.
- Make sure the same QoS settings applied to ms-teams.exe are also applied to ms-teams_modulehost.exe. Refer to this page for details: Implement Quality of Service (QoS) in Microsoft Teams
- DO NOT remove QoS settings of ms-teams.exe. Only add QoS settings for ms-teams_modulehost.exe.
[Compliance considerations:]
No compliance considerations identified, review as appropriate for your organization.
