Permission & Access Issues

Why External SharePoint Users Cannot Use @Mentions

WPS Editor Sep 25, 2026 868 views

Question details

Guest or external users are unable to use the @mention feature in SharePoint list item comments, despite having Contribute permissions.

Why External SharePoint Users Cannot Use @Mentions

Product: Microsoft SharePoint
Device & OS: not provided
Scenario: Collaborating with external users or guests on SharePoint lists and attempting to tag them or others in comments.
Observed behavior: External users can add comments to list items but are unable to @mention other users or themselves. Internal users also cannot @mention external guests.

Before you start

Verify your Microsoft 365 admin center settings to confirm whether the users experiencing the issue are classified as internal members or external guest accounts.

Solution 1Recommended

Understand SharePoint Cross-Tenant @Mention Limitations

Recognize that Microsoft 365 natively restricts guest or external accounts from mentioning users across different tenants, regardless of their permission levels.

Microsoft SharePoint currently does not support the @mentions feature for guest or external accounts across different tenants. This means external users cannot mention collaborators in files or lists outside their home tenant, and internal collaborators cannot mention them either.

Changing list permissions to 'Contribute' or granting group-based access will not resolve this structural limitation, as it is a tenant-level security design rather than a simple folder or list permission issue.

Confirm User Account Type

Check your Azure Active Directory or Microsoft 365 Admin Center to confirm if the affected users are listed as Guest accounts from another organization.

Use Standard Comments

Instruct external users to leave standard text comments on SharePoint list items without using the @ symbol, and rely on manual communication for notifications.

Submit Feature Feedback

If cross-tenant mentions are essential for your organizational workflow, submit your feature request directly to the official Microsoft Feedback Portal for SharePoint.

Understand SharePoint Cross-Tenant @Mention Limitations

By Design Limitation: This is an expected behavior in Microsoft 365 designed to protect tenant privacy and directory information from external exposure.

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Frequently Asked Questions

Can I fix the @mention issue for external users by giving them Full Control permissions?

No. The limitation is based on the account type (cross-tenant guest) rather than the permission level. Granting Full Control or Contribute access will not enable the @mention feature for external users in SharePoint.

Will internal users be able to @mention external guests in SharePoint?

No. Just as external users cannot mention internal collaborators, internal users are also restricted from @mentioning external guest accounts in SharePoint files and lists across different tenants.

Are there any workarounds for notifying external users in SharePoint lists?

Yes. Instead of using @mentions, you can set up Power Automate flows to send automated email notifications to specific external users whenever a SharePoint list item is created or modified.

Document & File Issues