MC1509801 - Microsoft Teams: Customize file extensions blocked by Weaponizable File Protection

Updated November 2, 2026: We have updated the timeline. Thank you for your patience. 

What and why

Microsoft Teams is expanding admin controls for Weaponizable File Protection. Admins will be able to customize which file extensions are blocked in Teams based on their organization’s security needs or continue using the Microsoft-recommended default list. This change provides greater flexibility to tailor file protection policies while maintaining a secure collaboration experience.

Rollout schedule

• General Availability (Worldwide): Beginning in early December 2026 (previously early November) and expected to complete by mid-December 2026 (previously mid-November)

Impact on your organization

Who is affected

• Organizations that use Weaponizable File Protection in Microsoft Teams

Platforms and services

• Microsoft Teams

What will happen

• Before this rollout, Microsoft defines the file extensions blocked by Weaponizable File Protection, and admins cannot customize the list.
• After this rollout, admins can define which file extensions are blocked for their organization or continue using the Microsoft-recommended default list.
• Organizations with Weaponizable File Protection enabled will continue using the Microsoft-recommended list by default.
• Organizations that continue using the Microsoft-recommended list will automatically receive future updates to that list.
• If an admin customizes the list, the organization will use the customized list and will no longer automatically receive future updates to the Microsoft-recommended list.
• The user experience will not change. Files with blocked extensions will continue to be blocked in Teams as they are today.

Screenshot 1 Customize file type view: 

Screenshot 2 Customize file type add view:

Action required and recommendations

No action is required. Organizations with Weaponizable File Protection enabled will continue using the Microsoft-recommended list by default.

If your organization wants to customize Weaponizable File Protection:

• Admins can add or remove file extensions based on their organization’s security needs.
• Admins can reset the configuration to the Microsoft-recommended default list at any time to resume receiving automatic updates.

Compliance considerations