The February 2025 EX1015484 incident explains why mail user objects with duplicate SMTP addresses are created for guest accounts. That’s a problem because Exchange Online can’t route messages to objects with duplicate email addresses. Fortunately, you can find out if any duplicates exist in your tenant with some PowerShell. Problems happen!
Mail contacts have long been used by Exchange organizations to provide an identity for external people. Contacts show up in the GAL to make it easy for users to send messages to external people and they can be included in distribution lists. The downside is that mail contacts are only available to Exchange Online. Perhaps the time is right to consider switching focus to Entra ID guest accounts? We explore the option here.
It’s easy to invite people to become guest users in a Microsoft 365 tenant, but some of the invitees never accept the invitation. Perhaps they don’t need to redeem the invitation to do work or maybe it’s because they don’t want to. In either case, Entra ID guest accounts with unredeemed invitations can accumulate and become stale. In this post, we discuss how to use PowerShell to find and remove those stale accounts in a safe manner.
Entra ID Guest Accounts have a habit of becoming stale or obsolete as time progresses. Guest accounts created to share documents or to be a member of a long-forgotten team or group remain in Azure AD until someone comes to clean them up. This article explains how we refreshed a popular script to use cmdlets from the Microsoft Graph PowerShell SDK to report guest accounts with different degrees of staleness.