*For this entry exists the more relevant or more recent entry MC1200576
check before: 2025-09-01
Product:
Microsoft 365 admin center, Teams, Windows
Platform:
Android, iOS, Mac, Online, Web, Windows Desktop, World tenant
Status:
Feature Rollout Status Not Supported
Change type:
Admin impact, New feature, Updated message, User impact
Details:
Summary:
Microsoft Teams will block messages containing weaponizable file types (e.g., executables) in chats and channels starting November 2025, enhancing security by preventing unsafe content sharing. The feature will be on by default at General Availability, with admins able to configure settings via the Teams Admin Center or PowerShell.
Details:
Updated November 17, 2025: The rollout of Weaponizable file type protection in Microsoft Teams is expected to finish before the end of November 2025 for General Availability (Worldwide). The previously announced update to make Weaponizable file protection setting in Messaging settings ON by default has been postponed to early 2026. A separate communication will be issued detailing the roll out schedule for the default-on change in advance.
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 complete by end of November. 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 end of November 2025 (previously mid-November).
Change Category:
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Scope:
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Release Phase:
Standard Release
Created:
2025-09-06
updated:
2025-11-18
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**
Please, look at the most relevant linked item for details
explanation for non-techies**
Microsoft Teams is enhancing its security measures by introducing a new feature that blocks certain types of files in chats and channels. Think of it like a security guard at the entrance of a building who checks for dangerous items before allowing people to enter. In this case, Microsoft Teams is the building, and the security guard is the new feature that checks messages for potentially harmful files, such as executable files that can carry malware.
Starting in November 2025, this feature will be automatically turned on for all users, meaning it will actively block messages containing these risky file types. If a message contains a blocked file, the recipient will see a notification that the message was blocked, but they won't be able to access the content. The sender will also be notified and can choose to edit and resend the message without the unsafe file.
For administrators, this feature can be managed through the Teams Admin Center, where they can adjust settings according to their organization's needs. It's like having the ability to set the security level at the building entrance, deciding what is allowed and what isn't.
The aim of this feature is to prevent the sharing of unsafe content that could lead to malware infections or other security breaches. By blocking these files, Microsoft Teams helps ensure a safer communication environment for all users.
** AI generated content. This information must be reviewed before use.
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change history
| Date | Property | old | new |
| 2025-11-18 | MC Last Updated | 10/30/2025 18:57:04 | 2025-11-17T18:08:15Z |
| 2025-11-18 | MC Messages | 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. | Updated November 17, 2025: The rollout of Weaponizable file type protection in Microsoft Teams is expected to finish before the end of November 2025 for General Availability (Worldwide). The previously announced update to make Weaponizable file protection setting in Messaging settings ON by default has been postponed to early 2026. A separate communication will be issued detailing the roll out schedule for the default-on change in advance.
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 complete by end of November. 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 end of November 2025 (previously mid-November). |
| 2025-11-18 | MC End Time | 12/16/2025 09:00:00 | 2025-12-31T09:00:00Z |
| 2025-11-18 | MC 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. | Microsoft Teams will block messages containing weaponizable file types (e.g., executables) in chats and channels starting November 2025, enhancing security by preventing unsafe content sharing. The feature will be on by default at General Availability, with admins able to configure settings via the Teams Admin Center or PowerShell. |
| 2025-11-17 | MC Feature Ring | Standard Release, Targeted Release | Standard Release |
| 2025-11-07 | MC Feature Ring | Standard Release | Standard Release, Targeted Release |
| 2025-11-07 | MC Feature Status | Feature Rollout Status Not Supported | |
| 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 2 weeks ago ago
