"More than one mailbox has the same e-mail address" error message when you try to manage a mailbox in a tenant organization in an Exchange Server 2010 SP1 Hosting mode environment

Symptoms

Consider the following scenario:

  • You install Microsoft Exchange Server 2010 Service Pack 1 (SP1) in Hosting mode by using the /hosting switch.

  • You create two tenant organizations (organization 1 and organization 2) in the Exchange Server 2010 SP1 environment.

  • Organization 1 has a mail-enabled user (user A).

  • You create an external contact for user A in organization 2.

  • The administrator of organization 1 tries to manage the mailbox of user A by using the Exchange Control Panel (ECP).

In this scenario, the administrator receives an ECP dialog box that contains the following error message:

More than one mailbox has the same e-mail address. To resolve this issue, contact your administrator.

Cause

This issue occurs because the ECP incorrectly looks up the user by using a global scope. Therefore, two objects that have the same Simple Mail Transfer Protocol (SMTP) address are found.

Resolution

To resolve this issue, install the following update rollup:

2661854 Description of Update Rollup 2 for Exchange Server 2010 Service Pack 2

Status

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

More Information

For more information about multi-tenant Exchange deployments, visit the following Microsoft website:

General information about multi-tenant Exchange deploymentsFor more information about the Hosting mode, visit the following Microsoft website:

General information about the Hosting modeFor more information about how to create a tenant organization, visit the following Microsoft website:

How to create a tenant organizationFor more information about the New-MailContact cmdlet, visit the following Microsoft website:

General information about the New-MailContact cmdlet

Need more help?

Expand your skills
Explore Training
Get new features first
Join Microsoft Insiders

Was this information helpful?

What affected your experience?

Any additional feedback? (Optional)

Thank you for your feedback!

×