MC1189656 - Upcoming Change to Teams Desktop Client on Windows

Updated December 17, 2025: We understand that implementing the current guidance involves considerable effort for administrators, and we are actively working to reduce this impact. We are exploring ways to make policy changes as seamless as possible, in close partnership with the Windows team.

Given this ongoing work, we recommend pausing any testing or configuration updates related to this feature. Updated instructions and revised guidance will be shared as part of the formal communication planned for January 2026.

Thank you for the valuable feedback we’ve received. We are currently reassessing the rollout timelines to ensure alignment with your needs and operational requirements. You can expect a formal update from us by mid to late January 2026.

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.

Updated rollout timing will be announced in January 2026

Note: Timelines may shift due to year-end feature flag rollout freeze.

• 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.

• 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.

No compliance considerations identified, review as appropriate for your organization.