MC1200576 – Teams admin center: Messaging safety defaults changing to “On” by default

Product:

Defender, Defender for Office 365, Defender XDR, Entra, Microsoft 365 admin center, Microsoft 365 Apps, Teams, Windows

Platform:

Android, iOS, Mac, Online, Web, Windows Desktop, World tenant

Status:

Launched

Change type:

Feature update, Admin impact

Links:

MC1148540
MC1148539
MC1147984

Details:

Summary:
Starting January 12, 2026, Microsoft Teams will enable messaging safety features by default, including weaponizable file type protection, malicious URL protection, and reporting incorrect detections. Existing custom settings remain unchanged. Admins should review and adjust settings before this date and inform helpdesk staff accordingly.

Details:
[Introduction]
We're improving messaging security in Microsoft Teams by enabling key safety protections by default. This update helps safeguard users from malicious content and provides options to report incorrect detections, reducing risk and improving collaboration security.
[When this will happen:]
Starting January 12, 2026, as announced in MC1148540, MC1148539, and MC1147984.

Change Category:
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Scope:
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Release Phase:
General Availability, Standard Release, Targeted Release

Created:
2025-12-20

updated:
2025-12-20

Task Type

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Docu to Check

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MS How does it affect me

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MS Preperations

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MS Urgency

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MS workload name

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linked item details

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summary for non-techies**

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Direct effects for Operations**

Weaponizable File Type Protection
Users may experience blocked messages containing weaponizable file types, leading to disruptions in communication and collaboration.
   - roles: End Users, Helpdesk Staff
   - references: https://learn.microsoft.com/microsoftteams/weaponizable-file-protection-teams

Malicious URL Protection
Users will see warning labels on messages containing malicious URLs, which may cause confusion and hinder workflow if not communicated properly.
   - roles: End Users, Helpdesk Staff
   - references: https://learn.microsoft.com/microsoftteams/malicious-url-protection-teams

Reporting Incorrect Detections
Users may report false positives, which could lead to increased workload for helpdesk staff if they are not prepared to handle these reports.
   - roles: End Users, Helpdesk Staff
   - references: https://learn.microsoft.com/microsoftteams/end-user-reporting-security#user-experience-in-teams--report-not-a-security-concern

Configutation Options**

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Opportunities**

Enhanced User Reporting Mechanism
The new feature allowing users to report incorrectly flagged messages will enhance user engagement and feedback mechanisms. This will help improve the accuracy of security detections and reduce user frustration with false positives.
   - next-steps: Educate users on how to utilize the reporting feature effectively. Create training sessions and documentation to ensure all users understand the process and importance of reporting.
   - roles: IT Security Team, End Users, Helpdesk Staff
   - references: https://learn.microsoft.com/microsoftteams/end-user-reporting-security#user-experience-in-teams--report-not-a-security-concern

Proactive Security Configuration Review
With the messaging safety defaults changing, there is an opportunity to conduct a comprehensive review of current security settings across the organization. This proactive approach can ensure that all teams are adequately protected against potential threats and that the configurations align with organizational policies.
   - next-steps: Schedule a review meeting with IT and security teams to assess current settings. Prepare a checklist based on new defaults and create an action plan for any necessary adjustments.
   - roles: IT Administrators, Compliance Officers, Security Analysts
   - references: https://learn.microsoft.com/microsoftteams/malicious-url-protection-teams

Streamlined Helpdesk Support Processes
The change in messaging safety defaults necessitates updating helpdesk protocols and documentation. This presents an opportunity to streamline support processes, potentially reducing ticket resolution times and improving user satisfaction.
   - next-steps: Update internal documentation and create a FAQ section addressing common user concerns related to the new settings. Train helpdesk staff on these changes to enhance their support capabilities.
   - roles: Helpdesk Staff, IT Support Managers, End Users
   - references: https://learn.microsoft.com/microsoftteams/weaponizable-file-protection-teams

Potentional Risks**

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IT Security**

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explanation for non-techies**

Starting January 12, 2026, Microsoft Teams will automatically enable certain messaging safety features. This means that without any action on your part, protections like blocking dangerous file types, warning about harmful links, and allowing users to report false security alerts will be active. Think of it like a car that now comes with automatic seatbelts and airbags as standard features, enhancing safety without needing you to install them separately.

For those who haven't changed these settings before, it's like moving into a new house where the smoke detectors are already installed and working. You don't have to do anything unless you want to customize or turn them off. If you've already set your preferences, nothing will change for you, similar to how you might have adjusted the thermostat in your home to your liking.

These changes are designed to protect users from potential threats while using Teams, much like how security systems in buildings help prevent unauthorized access. If you prefer different settings, you can still adjust them before the change takes effect. It's like choosing to lock certain doors in your office while leaving others open based on your security needs.

Admins should review these settings and inform helpdesk staff, ensuring everyone is aware of the new default protections. This is akin to a building manager notifying tenants about new security measures being implemented in the complex.