check before: 2025-09-01
Product:
Microsoft 365 admin center, Teams, Windows
Platform:
Android, iOS, Mac, Online, Web, Windows Desktop, World tenant
Status:
Rolling out
Change type:
Admin impact, New feature, Updated message, User impact
Links:
Details:
Summary:
Microsoft Teams will block messages containing unsafe, weaponizable file types in chats and channels starting November 3, 2025. This protection, enabled by default at General Availability, notifies senders and recipients when messages are blocked. Admins can configure settings via the Teams Admin Center or PowerShell.
Details:
Updated October 30, 2025: We have updated the content. Thank you for your patience.
Introduction
Microsoft Teams is introducing a new protection feature that blocks messages containing weaponizable file types-such as executables-in chats and channels. This helps reduce the risk of malware and file-based attacks by preventing unsafe content from being shared. This message applies to Teams for Windows desktop, Teams for Mac desktop, Teams for the web, and Teams for iOS/Android.
This message is associated with Roadmap ID 499892.
When this will happen
General Availability begins November 3 and will take 2-3 weeks to complete. At GA, "Scan messages for file types that are not allowed" will default to ON, and protection will apply if any participant in a conversation has it enabled.
To use a different setting, go to Teams admin center → Messaging settings → Scan messages for file types that are not allowed, select your preference, and click Save before GA.
Note: Simply viewing the page without saving will not override the default, but settings already saved during Targeted Release will persist.
Targeted release (Worldwide): Starts early September 2025; expected to complete by mid-September 2025.
General Availability (Worldwide): Starts early November 2025; expected to complete by mid-November 2025.
Change Category:
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Scope:
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Release Phase:
General Availability, Targeted Release
Created:
2025-09-06
updated:
2025-11-02
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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Pictures
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summary for non-techies**
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Direct effects for Operations**
Blocked Message Delivery
Messages containing weaponizable file types will be blocked, preventing users from accessing important content and attachments, which may disrupt workflows and communication.
- roles: End Users, Team Leaders
- references: https://learn.microsoft.com/microsoftteams/weaponizable-file-protection-teams, https://www.microsoft.com/microsoft-365/roadmap?filters=&searchterms=499892
User Experience Disruption
Users will receive notifications about blocked messages, which may lead to confusion and frustration, especially if they are unaware of the new protection feature.
- roles: End Users, Support Staff
- references: https://learn.microsoft.com/microsoftteams/weaponizable-file-protection-teams, https://www.microsoft.com/microsoft-365/roadmap?filters=&searchterms=499892
Increased Support Requests
The introduction of this feature without prior preparation may lead to an increase in support requests from users who are confused about the new message blocking, impacting IT support resources.
- roles: Support Staff, IT Administrators
- references: https://learn.microsoft.com/microsoftteams/weaponizable-file-protection-teams, https://www.microsoft.com/microsoft-365/roadmap?filters=&searchterms=499892
Configutation Options**
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Opportunities**
Enhanced User Education and Awareness
With the introduction of file protection, there is an opportunity to educate users about safe file sharing practices and the types of files that are blocked. This can lead to a more security-conscious culture within the organization.
- next-steps: Develop training materials and sessions focusing on file sharing best practices and the implications of the new protection feature. Schedule regular awareness campaigns to reinforce these practices.
- roles: IT Administrators, Compliance Officers, HR Managers
- references: https://learn.microsoft.com/microsoftteams/weaponizable-file-protection-teams, https://www.microsoft.com/microsoft-365/roadmap?filters=&searchterms=499892
Improved IT Security Policies
The new protection feature can be leveraged to review and enhance existing IT security policies. By aligning policies with the new capabilities, organizations can ensure a comprehensive approach to file sharing and data protection.
- next-steps: Conduct a security policy review to incorporate the new Teams file protection feature. Update the IT security framework to reflect changes in file handling and sharing practices.
- roles: IT Security Managers, Compliance Officers, Risk Management Teams
- references: https://learn.microsoft.com/microsoftteams/weaponizable-file-protection-teams, https://www.microsoft.com/microsoft-365/roadmap?filters=&searchterms=499892
Streamlined IT Support Operations
The automatic blocking of unsafe file types can reduce the number of security incidents related to file sharing, allowing IT support teams to focus on more critical issues and improving overall efficiency.
- next-steps: Analyze historical data on file-sharing incidents to estimate potential reductions in support tickets. Adjust IT support resources and workflows to accommodate this change.
- roles: IT Support Teams, IT Managers, Operations Managers
- references: https://learn.microsoft.com/microsoftteams/weaponizable-file-protection-teams, https://www.microsoft.com/microsoft-365/roadmap?filters=&searchterms=499892
Potentional Risks**
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IT Security**
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explanation for non-techies**
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** AI generated content. This information must be reviewed before use.
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change history
| Date | Property | old | new |
| 2025-11-02 | MC Feature Status | Feature Rollout Status Not Supported | |
| 2025-10-30 | MC Messages | Updated September 9, 2025: We have updated the content. Thank you for your patience.
Introduction Microsoft Teams is introducing a new protection feature that blocks messages containing weaponizable file types-such as executables-in chats and channels. This helps reduce the risk of malware and file-based attacks by preventing unsafe content from being shared. This message applies to Teams for Windows desktop, Teams for Mac desktop, Teams for the web, and Teams for iOS/Android. This message is associated with Roadmap ID 499892. When this will happen Targeted release (Worldwide): Starts early September 2025; expected to complete by mid-September 2025. General Availability (Worldwide): Starts early November 2025; expected to complete by mid-November 2025. | Updated October 30, 2025: We have updated the content. Thank you for your patience.
Introduction Microsoft Teams is introducing a new protection feature that blocks messages containing weaponizable file types-such as executables-in chats and channels. This helps reduce the risk of malware and file-based attacks by preventing unsafe content from being shared. This message applies to Teams for Windows desktop, Teams for Mac desktop, Teams for the web, and Teams for iOS/Android. This message is associated with Roadmap ID 499892. When this will happen General Availability begins November 3 and will take 2-3 weeks to complete. At GA, "Scan messages for file types that are not allowed" will default to ON, and protection will apply if any participant in a conversation has it enabled. To use a different setting, go to Teams admin center → Messaging settings → Scan messages for file types that are not allowed, select your preference, and click Save before GA. Note: Simply viewing the page without saving will not override the default, but settings already saved during Targeted Release will persist. Targeted release (Worldwide): Starts early September 2025; expected to complete by mid-September 2025. General Availability (Worldwide): Starts early November 2025; expected to complete by mid-November 2025. |
| 2025-10-30 | MC Title | New file protection in Teams chat and channels blocks unsafe content | (Updated) New file protection in Teams chat and channels blocks unsafe content |
| 2025-10-30 | MC Last Updated | 09/09/2025 17:19:02 | 2025-10-30T18:57:04Z |
| 2025-10-30 | MC Summary | Microsoft Teams will block messages containing weaponizable file types (e.g., executables) in chats and channels to reduce malware risks. This feature starts targeted release in September 2025 (off by default) and general availability in November 2025 (on by default). Admins can enable it via Teams Admin Center or PowerShell. | Microsoft Teams will block messages containing unsafe, weaponizable file types in chats and channels starting November 3, 2025. This protection, enabled by default at General Availability, notifies senders and recipients when messages are blocked. Admins can configure settings via the Teams Admin Center or PowerShell. |
| 2025-10-16 | MC Feature Ring | Standard Release, Targeted Release | Standard Release |
| 2025-09-11 | MC Feature Ring | Targeted Release | Standard Release, Targeted Release |
| 2025-09-10 | MC prepare | https://learn.microsoft.com/microsoftteams/malicious-url-protection-teams
https://learn.microsoft.com/microsoftteams/security-compliance-overview https://www.microsoft.com/microsoft-365/roadmap?filters=&searchterms=499892 | https://learn.microsoft.com/microsoftteams/weaponizable-file-protection-teams
https://www.microsoft.com/microsoft-365/roadmap?filters=&searchterms=499892 |
| 2025-09-10 | MC MessageTagNames | New feature, User impact, Admin impact | Updated message, New feature, User impact, Admin impact |
| 2025-09-10 | MC Summary | Microsoft Teams will block messages containing unsafe, weaponizable file types in chats and channels starting September 2025 (targeted release) and November 2025 (general availability). Admins can enable this protection via Teams Admin Center or PowerShell. Blocked files include executables and other risky formats to reduce malware risks. | Microsoft Teams will block messages containing weaponizable file types (e.g., executables) in chats and channels to reduce malware risks. This feature starts targeted release in September 2025 (off by default) and general availability in November 2025 (on by default). Admins can enable it via Teams Admin Center or PowerShell. |
| 2025-09-10 | MC Last Updated | 09/06/2025 00:03:47 | 2025-09-09T17:19:02Z |
| 2025-09-10 | MC Messages | Introduction
Microsoft Teams is introducing a new protection feature that blocks messages containing weaponizable file types-such as executables-in chats and channels. This helps reduce the risk of malware and file-based attacks by preventing unsafe content from being shared. This message applies to Teams for Windows desktop, Teams for Mac desktop, Teams for the web, and Teams for iOS/Android. This message is associated with Roadmap ID 499892. When this will happen Targeted release (Worldwide): Starts early September 2025; expected to complete by mid-September 2025. General Availability (Worldwide): Starts early November 2025; expected to complete by mid-November 2025. | Updated September 9, 2025: We have updated the content. Thank you for your patience.
Introduction Microsoft Teams is introducing a new protection feature that blocks messages containing weaponizable file types-such as executables-in chats and channels. This helps reduce the risk of malware and file-based attacks by preventing unsafe content from being shared. This message applies to Teams for Windows desktop, Teams for Mac desktop, Teams for the web, and Teams for iOS/Android. This message is associated with Roadmap ID 499892. When this will happen Targeted release (Worldwide): Starts early September 2025; expected to complete by mid-September 2025. General Availability (Worldwide): Starts early November 2025; expected to complete by mid-November 2025. |
| 2025-09-10 | MC How Affect | Once enabled, Teams will automatically block messages that include weaponizable file types. This applies to both internal and external conversations.
Recipients will see a notification that a message was blocked but cannot access the content. Senders will receive a notification and can edit and resend the message without the unsafe file. Targeted release vs. General Availability behavior: Targeted release: Protection is enforced only when all organizations in the conversation have the feature enabled. This feature is off by default and requires admin activation. General Availability: Protection is enforced if at least one participant has the feature enabled. This feature is on by default. Admin settings saved during Targeted Release will remain unchanged. What you can do to prepare Admins can enable this protection in the Teams Admin Center: Go to the Teams Admin Center Navigate to Messaging Settings Turn on the setting: Scan messages for file types that are not allowed Alternatively, use PowerShell with the -FileTypeCheck parameter. Once enabled, all users in your tenant will begin seeing file protection applied in their messages. Blocked file types include: ace, ani, apk, app, appx, arj, bat, cab, cmd, com, deb, dex, dll, docm, elf, exe, hta, img, iso, jar, jnlp, kext, lha, lib, library, lnk, lzh, macho, msc, msi, msix, msp, mst, pif, ppa, ppam, reg, rev, scf, scr, sct, sys, uif, vb, vbe, vbs, vxd, wsc, wsf, wsh, xll, xz, z Learn more: Overview of security and compliance - Microsoft Teams | Microsoft Learn (will be updated before rollout) Malicious URL Protection in Microsoft Teams Compliance considerations Compliance AreaExplanation Does the change modify how users can access, export, delete, or correct their personal data within Microsoft 365 services?Blocked messages are not delivered, which may affect access to the original message content. Recipients of messages with disallowed file types will not receive the message or its attachments. | Once enabled, Teams will automatically block messages that include weaponizable file types. This applies to both internal and external conversations.
Recipients will see a notification that a message was blocked but cannot access the content. Senders will receive a notification and can edit and resend the message without the unsafe file. Targeted release vs. General Availability behavior: Targeted release: Protection is enforced only when all organizations in the conversation have the feature enabled. This feature is off by default and requires admin activation. General Availability: Protection is enforced if at least one participant has the feature enabled. This feature is on by default. Admin settings saved during Targeted Release will remain unchanged. What you can do to prepare Admins can enable this protection in the Teams Admin Center: Go to the Teams Admin Center Navigate to Messaging Settings Turn on the setting: Scan messages for file types that are not allowed Alternatively, use PowerShell with the -FileTypeCheck parameter. Once enabled, all users in your tenant will begin seeing file protection applied in their messages. Blocked file types include: ace, ani, apk, app, appx, arj, bat, cab, cmd, com, deb, dex, dll, docm, elf, exe, hta, img, iso, jar, jnlp, kext, lha, lib, library, lnk, lzh, macho, msc, msi, msix, msp, mst, pif, ppa, ppam, reg, rev, scf, scr, sct, sys, uif, vb, vbe, vbs, vxd, wsc, wsf, wsh, xll, xz, z Learn more: Weaponizable File Protection in Microsoft Teams Compliance considerations Compliance AreaExplanation Does the change modify how users can access, export, delete, or correct their personal data within Microsoft 365 services?Blocked messages are not delivered, which may affect access to the original message content. Recipients of messages with disallowed file types will not receive the message or its attachments. |
| 2025-09-08 | MC Feature Ring | Targeted Release |
Last updated 1 hour ago
