Unable to always upload to chat

Hi @Gem,

Thank you for reaching out regarding the issue with uploading files in Teams meeting chats when external participants join.

According to Microsoft’s official roadmap for this feature Microsoft 365 Roadmap | Microsoft 365, the ability to share files in chats with external users is a newly introduced capability and is currently in the rolling out phase. This means the feature may not yet be fully available in your region or tenant.

Additionally, if the feature has been rolled out to your tenant, your IT administrator must enable it (disabled by default) by setting the FileSharingInChatWithExternalUsers policy to Enabled using PowerShell. For reference: Set-CsTeamsFilesPolicy (MicrosoftTeams) | Microsoft Learn. IT admins also need to configure external sharing settings in SharePoint Admin Center to allow sharing with “Anyone” or “New and existing guests” so external users can access the shared files.

With that in mind, the workaround you can try in the meantime is to upload the file to OneDrive or SharePoint, copy the link, and paste it into the Teams chat. Please note that IT admins also need to configure external sharing settings in SharePoint Admin center to "Anyone" so the external users can access the shared files.

Additionally, if your organization has had this feature enabled for some time and the issue has only started occurring recently, it may require further back-end investigation. In this case, please have your IT admin contact Microsoft Support for assistance.

A technical support engineer can then initiate a remote session to examine the situation, validate backend settings, and run any necessary synchronization tools to resolve the issue. If further analysis is needed, they can escalate the case to a specialized team for deeper investigation.

For detailed instructions on how to get support, please share this link to your IT admin: Get support - Microsoft 365 admin.   

Please note that forum moderators do not have access to user account settings and cannot assist with logging in, resetting passwords, or changing access rights. While we do not have access to internal systems or administrative tools required to resolve account-specific or backend-related issues, we’ll continue doing our best to support you within the scope of our responsibilities.   

I hope this information is helpful. Thank you for your patience and your understanding. If you have any questions or need further assistance, please feel free to share them in the comments on this post so I can continue to support you.

I look forward to continuing the conversation.

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The issue you are experiencing with the inability to upload files to chat in Microsoft Teams when external users join may be related to the permissions and capabilities set for external participants. In Microsoft Teams, the ability to send and receive file attachments can vary based on the roles assigned to users in the meeting, especially when external users are involved.

Here are some steps you can take to troubleshoot and possibly resolve the issue:

1. Check Meeting Policies: Ensure that the meeting policies allow file sharing for external users. The Teams administrator can configure these settings in the Teams admin center.
2. Test with Different External Users: Since the issue is inconsistent, try testing with different external users to see if the problem persists across all external participants or if it is specific to certain users.
3. Run Diagnostics: If the issue continues, consider running a self-diagnostics tool available for Microsoft 365 admin users. This tool can help identify potential issues affecting file uploads.
4. Contact Support: If none of these steps resolve the issue, you may need to create a service request with Microsoft support, providing details about the problem and any relevant logs.

These steps should help you identify the cause of the issue and find a workaround or resolution.