Teams: Share Files with External Users

Key insights

• Attach File may disappear in chats with external users because Teams blocks file attachments by default for security.
  Admins must enable the setting in the Teams Files Policy to restore the Attach File option for external chats.
• PowerShell steps to enable file sharing: install the Teams PowerShell module, authenticate as an admin, run Connect-MicrosoftTeams, check your policy with Get-CsTeamsFilesPolicy, then enable sharing with Set-CsTeamsFilesPolicy -Identity Global -FileSharingInChatsWithExternalUsers Enabled.
  Run these commands from an admin account and verify the policy change after you apply it.
• Scope changes to specific users instead of the whole tenant by targeting the policy Identity (for example, use a custom policy name instead of Global).
  This lets you enable external file sharing only for selected admins or teams.
• Where files live: shared files are saved in the sender’s OneDrive and follow SharePoint/OneDrive sharing rules.
  Sensitivity labels, domain restrictions and malicious-link protections still apply, so security controls remain enforced.
• Group-chat behavior matters: only current members can open files shared at the time of sharing.
  If someone joins later, they won’t automatically get access to older shared files unless permissions are updated.
• Audit and governance are essential: review Files Policy settings regularly, test sharing after changes, and keep logs of who can share externally.
  Enable the feature only where business need and risk controls align.

Keywords

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