File Sharing on 1:1 or Multiple Chats on Teams Error

Cole Vivienne 0 Reputation points
2026-08-25T23:50:28.7666667+00:00

When I try to share files within a group chat or 1:1 chat the other party cannot view the files, from access denied despite the permissions being correct. A customer support agent told me that it could be due to duplicate entities in our tenant. Could you provide me with support?

Microsoft Teams | Microsoft Teams for business | Chats | Share photos, files, and video
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  1. BabybooHN 2,450 Reputation points Independent Advisor
    2026-08-26T00:23:00.3366667+00:00

    Dear @Cole Vivienne

    If customer support agent said that the issue stems from a user identity mismatch or duplication within your Azure AD (Entra ID) tenant or the SharePoint User Profile Service (UPS), the following occurs: when a user's email address or Principal Name is reused or duplicated, Teams creates a OneDrive folder for 1:1 or group chats linked to a duplicate SharePoint Security Identifier (SID). Consequently, although file access permissions appear correct in the user interface, the recipient's identity points to a different account instance at the system level, resulting in an "Access Denied" error.

    Here is the step-by-step solution to resolve this core issue:

    Step 1: Check and Remove Duplicate Entities in Azure AD / Entra ID

    • Open the Microsoft 365 Admin Center > Microsoft Entra admin center and go to Identity > Users > All users.
    • Search for both the sender’s and receiver’s email address/User Principal Name (UPN).
    • Check Deleted users to ensure there are no lingering soft-deleted duplicate accounts with the same email address. If found, permanently delete the stale object.

    Step 2: Clear Teams Client Cache (Workaround for End Users)

    Ask both users to clear their local Teams client cache so identity tokens refresh properly:

    • Fully close Microsoft Teams (right-click the tray icon and select Quit).
    • Press Win + R, type %appdata%\Microsoft\Teams, and delete all files in that folder (or %localappdata%\Packages\MSTeams_8wekyb3d8bbwe for new Teams).
    • Restart Teams and re-share the file.

    Please refer to this document: Clear the Teams client cache

    Step 3: Clear Stale User Profiles in SharePoint Online If the identity was recently re-created, SharePoint Online may still retain the old User Info List entry:

    As a SharePoint Administrator, open the SharePoint Online Management Shell. Please refer to this document for step by step code: Remove-SPOUser

    Connect to your tenant admin service:

    Connect-SPOService -Url https://<yourtenant>-admin.sharepoint.com

    Run Get-SPOUser to inspect the user account's PUID/SID across the affected chat site/OneDrive.

    If a duplicate or orphaned profile exists, remove the stale user profile from the site collection using:

    Remove-SPOUser -Site https://<yourtenant>-my.sharepoint.com/personal/<user_folder> -LoginName <user_UPN>

    For detailed official guidance on fixing identity synchronization and profile mismatches in SharePoint/Teams, you can refer to Microsoft's official documentation: Fix site user ID mismatch in SharePoint or OneDrive.

    Please let me know if this helps resolve the error or if you need assistance with specific PowerShell commands.

    If the answer is helpful, please click "Yes" and kindly upvote it. If you have extra questions about this answer, please click "Comment".   

    Note: Please follow the steps in the forum document to enable e-mail notifications if you want to receive the related email notification for this thread.

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  2. AI answer

    2026-08-25T23:50:49.4+00:00

    For Teams chat file-sharing issues in 1:1 or group chats, the supported causes in the available guidance are permission and sharing-setting problems in OneDrive or SharePoint, not duplicate entities in the tenant.

    Use this troubleshooting path:

    1. Check whether the failure is in a large chat.
      • If the chat has more than 100 participants, file sharing can fail when the link type is People currently in this chat.
      • Change the file’s sharing setting to:
        • Anyone if the chat includes people outside the organization, or
        • People in your organization if everyone is internal.
      • If those options are disabled, an admin must enable the corresponding SharePoint sharing settings.
    2. If the file was shared in a normal Teams chat and recipients get You don't have access to this file, check the sender’s OneDrive site.
      • Sign in to OneDrive.
      • Select Settings > OneDrive Settings > More Settings.
      • Under Features and storage, select Site Collection Features.
      • Find Limited-access user permission lockdown mode and select Deactivate.
      • This feature can block access to files shared from Teams chat even when the file is stored in OneDrive.
    3. If guests or external users are involved, verify SharePoint and OneDrive sharing configuration.
      • In Teams chat and channels, file sharing depends on SharePoint and OneDrive sharing settings.
      • In the SharePoint admin center, go to Policies > Sharing and make sure sharing is set to allow guest access with one of these levels:
        • Existing guests
        • Anyone
        • New and existing guests
      • If using external federated chats, file sharing must also be enabled by admin PowerShell with Set-CsTeamsFilesPolicy -Identity Global -FileSharingInChatsWithExternalUsers Enabled.
      • Changes can take several hours to propagate.
    4. If file sharing is in external chats, confirm the expected behavior.
      • When file sharing is turned off for external chats, the paperclip attachment option is hidden and users can only paste existing links.
      • When it is turned on, senders may still need to manually adjust file permissions, and external recipients may need to request access.
    5. If the issue is internal user to internal user in a 1:1 chat, focus on OneDrive/SharePoint rather than Teams chat itself.
      • The documented issue is commonly tied to the underlying OneDrive or SharePoint permissions and site features.
      • Microsoft 365 admins can also run the built-in diagnostics for Teams chat file-access issues where available.

    If the scenario is specifically “permissions look correct but access is still denied,” the strongest documented check is disabling Limited-access user permission lockdown mode on the OneDrive site that stores the shared file.

    AI-generated content may be incorrect. Read our transparency notes for more information.

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