Microsoft Teams: File attachment control now enabled by default in external 1:1 and group chats

Microsoft Teams now enables automatic file and Loop component sharing by default in external 1:1, group, and meeting chats, improving collaboration. Admins can disable this via policy. Guest users can share files from their home tenant. Rollout starts October 2025, completing worldwide by January 2026. Introduction We’re improving external collaboration in Microsoft Teams by enabling file attachments and Loop sharing in 1:1, group and meeting chats with external users. This update improves the collaboration experience for Files and Loop and add a new control for IT admins. Specifically, Files and Loop components will be shared automatically with external participants in the chat and won’t require any action by the sender by default. Additionally, Entra B2B Guests in your organization will be able to attach and share files from their home tenant’s OneDrive or SharePoint.  This change applies to Teams for Windows desktop, Mac desktop, and web and is associated with Roadmap ID 492625. Screenshot 1: Files are automatically provisioned. View image in new tab Screenshot 2: Files shared have an external label and always open on Web. View image in new tab When this will happen: Targeted Release: Rollout begins late October 2025; expected to complete by mid-November 2025 General Availability (Worldwide): Rollout begins mid-January 2026 How this affects your organization: Who is affected: All Microsoft Teams users in your organization who participate in 1:1, group, or meeting chats with external users, including guest and Teams for Free users. What will happen: With this update: Unless the user chooses to share File and Loop by pasting links, external users in chat will be automatically provisioned to allow frictionless collaboration. You can disable automatic provisioning and have the user change permissions manually by using policy controls. If disabled, users will have to manually provision the file to users in the chat. Guest users will be able to upload files from their home tenant’s OneDrive and SharePoint. Files shared by external users will continue to display an External tag for clarity. Loop components will now be rendered inside external chats in Teams. Recipients will access File and Loop components as B2B guests within the resource […]

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