Issue resolved

User impact: Admins provisioning guest user mailboxes in Exchange Online may see that duplicate mailboxes are created.

More info: As a result of duplicate mailboxes being provisioned, user email addressed to the newly created guest user mailboxes may fail to deliver.

Current status: Our investigation has determined that a recent update to the data pathways leveraged to provision new guest user mailboxes in Exchange Online exposed an error that's causing some guest user data to be duplicated during provisioning, leading to impact. We're evaluating potential methods to address the provisioning error and resolve this issue.

Scope of impact: Any admin provisioning guest user mailboxes in Exchange Online may be impacted.

Root cause: A recent update to the data pathways leveraged to provision new guest user mailboxes in Exchange Online exposed an error that's causing some guest user data to be duplicated during provisioning, leading to impact.

Next update by: Monday, February 24, 2025, at 6:30 PM UTC