Forum Discussion
Sharing with an external user who has changed their email
I have had an issue with trying to share a folder with somebody who changed their email from, for illustrative purposes only, mailto:email address removed for privacy reasons to mailto:email address removed for privacy reasons. because his company EW had merged with Elsewhere. I believe that the second email was an alias for the first as both his actual addresses will reach him. The issue was that when I went to share a folder with his new email it would default back to his original email every single time. Eventually our IT department deleted all trace of his original email from Sharepoint which then recognised and allowed me to share with his new email.
My question is - how does Sharepoint know these two different emails are the same person? Is it randomly deciding there is enough similarity in the email addresses- which in my view would be very dangerous, or does it know that both domains are registered to the same organisation?
1 Reply
SharePoint is not matching addresses by textual similarity or domain ownership. It resolves an identity object—usually a Microsoft Entra B2B guest—and caches it in the site’s User Information List. An alias, changed mail property, or stale cache can display the old address while targeting the same object.
Ask an Entra administrator to locate the guest and verify its object ID, mail, otherMails, and identities instead of creating a duplicate. If the person must sign in with the new address, update the email and use Reset redemption status. Microsoft documents that this preserves the guest’s object ID, group memberships, and app assignments while sending a new invitation.
After redemption, test sharing by entering the full new address. If SharePoint still resolves the obsolete value, an administrator can remove the stale site-level UserInfo entry following Microsoft guidance, then resolve the guest again. Audit links first so access is not accidentally lost.
