Recreated user is unable to acces shared file in MS Teams.

This is a known issue in Microsoft 365 environments when:

• A user is deleted from Active Directory (AD) or Microsoft 365.
• Later, a new account is created with the same User Principal Name (UPN).
• The new account gets a new Object ID, but SharePoint and OneDrive still reference the old ID in their internal UserInfo lists.

This mismatch causes:

• Access Denied errors
• File download issues in Teams
• Permission problems in SharePoint/OneDrive

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✅ Recommended Fixes

1. Run Microsoft’s “Site User ID Mismatch” Diagnostic

Use the Microsoft 365 Admin Center to run the diagnostic:

• Go to: Fix site user ID mismatch [learn.microsoft.com]
• This tool will:
  • Detect mismatched IDs.
  • Remove the old user reference.
  • Re-sync permissions for the new account.

⚠️ Note: This may take up to 24 hours to fully propagate changes.

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2. Manually Remove Old User from SharePoint Site Collection

If the diagnostic doesn’t help, manually remove the old user:

• Navigate to:
  https://<yourdomain>.sharepoint.com/sites/<sitename>/_layouts/15/people.aspx?MembershipGroupId=0
• Find the old user entry (may appear as domain\username or email).
• Select and delete the user from the site collection.
• Re-share the site or files with the new user account.

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3. Check Teams File Permissions

Since Teams stores files in SharePoint/OneDrive:

• Right-click the file in Teams → Manage Access
• Ensure the new user is listed and has download permissions
• If not, re-share the file directly from SharePoint or OneDrive

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4. Clear Teams Cache (Client-Side)

Ask the user to:

• Sign out of Teams
• Clear Teams cache:
  • Windows: Delete %appdata%\Microsoft\Teams folder
• Sign back in

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5. PowerShell Option (Advanced)

If you manage multiple sites and want to automate cleanup:

• Use PnP.PowerShell to:
  • Detect mismatched IDs
  • Remove old users across multiple sites
  • Reassign permissions