Applies to: Exchange Server 2007 SP3, Exchange Server 2007 SP2, Exchange Server 2007 SP1, Exchange Server 2007
Topic Last Modified: 2007-01-30

In Microsoft Exchange Server 2007, each mailbox consists of an Active Directory directory service user and the mailbox data that is stored in the Exchange mailbox database. (For an illustration of the components of a mailbox, see Figure 1.) All configuration data for a mailbox is stored in the Exchange attributes of the Active Directory user object. The mailbox database contains the mail data that is in the mailbox associated with the user account.

When you create a mailbox for a new or existing user, the Exchange attributes that are required for a mailbox are added to the user object in Active Directory. The associated mailbox object in the Exchange mailbox database is not created until the mailbox either receives a message or the user logs on to it. If you create a new mailbox, and then remove or disable that mailbox before the mailbox object in the Exchange mailbox database is created, it will not be available as a disconnected mailbox.

Parts that make up a mailbox

A disconnected mailbox is a mailbox object in an Exchange mailbox database that is not associated with an Active Directory user account. When you remove or disable a mailbox, the data that is stored in the Exchange mailbox database is no longer associated with the user account in Active Directory and becomes a disconnected mailbox.

If you remove a mailbox, the mailbox data that is stored in the Exchange mailbox database is marked for deletion and the associated user account is also deleted from Active Directory. To retain the user account and only disassociate the mailbox data from the user account, you must disable the mailbox. For detailed instructions, see How to Disable a Mailbox.

To provide a method for recovering mailbox data without having to restore the entire mailbox database, disconnected mailboxes are retained in the mailbox database for a specific amount of time. By default, Exchange retains a disconnected mailbox for 30 days. During this time, the disconnected mailbox can be recovered by associating it with an existing Active Directory user account. To learn more about deleted mailbox retention, see Configuring Deleted Mailbox and Deleted Item Retention.

Working with Disconnected Mailboxes

There are two operations you can perform on a disconnected mailbox:

  • Connect it to an existing user account in Active Directory

  • Permanently delete it from the Exchange mailbox database

Connecting a Disconnected Mailbox

During the time a disconnected mailbox is retained in the Exchange mailbox database, you can connect it to an existing Active Directory user account that is not associated with another mailbox. Scenarios in which you may want to connect a mailbox include the following:

  • You disabled a mailbox and now want to reconnect the mailbox to an Active Directory user account.

  • You removed a mailbox by using the Remove-Mailbox cmdlet without the Permanent or StoreMailboxIdentity parameters and now want to reconnect the mailbox to a different Active Directory user account.

  • You want to convert a user mailbox to a linked mailbox that is associated with a user account external to the forest in which your Exchange organization exists. The resource forest scenario is an example of when you would want to associate a mailbox with an external account. In a resource forest scenario, user objects in the Exchange forest have mailboxes, but the user objects are disabled for logon. You must associate these mailbox objects in the Exchange forest with enabled user objects in the external accounts forest.

You can use the Connect-Mailbox cmdlet in the Exchange Management Shell or the Connect Mailbox wizard in the Exchange Management Console to connect a mailbox. The Connect Mailbox wizard is available from the action pane when you select the Disconnected Mailbox node under Recipient Configuration. For detailed instructions about how to connect a disconnected mailbox, see How to Connect a Mailbox.

After you connect a mailbox to an existing Active Directory user account, that user account becomes the owner of the mailbox and has full access to any content within the mailbox.

Permanently Deleting a Disconnected Mailbox

Exchange retains disconnected mailboxes in the mailbox database based on the deleted mailbox retention settings configured for that mailbox database. After the specified retention period, a disconnected mailbox is permanently deleted from the Exchange mailbox database.

You can also permanently delete a disconnected mailbox at any time by using the Remove-Mailbox cmdlet in the Exchange Management Shell. To do this, you need to set the Permanent parameter to $true when you run the command.

If you want to permanently delete the data within the mailbox database for a previously disconnected mailbox, you must use the StoreMailboxIdentity parameter with the Remove-Mailbox cmdlet. You can use the Get-MailboxStatistics cmdlet to determine the value you need to supply to the StoreMailboxIdentity parameter for a disconnected mailbox. For an example of this scenario, see the third code example in the reference topic Remove-Mailbox.

For detailed syntax and parameter information, see the Remove-Mailbox and Get-MailboxStatistics reference topics.

For More Information

For detailed information about how to connect a disconnected mailbox, see How to Connect a Mailbox.

For more information about deleted mailbox retention, see Configuring Deleted Mailbox and Deleted Item Retention.

For more information about the Exchange Management Shell cmdlets that relate to disconnected mailboxes, see the following topics:

To learn more about mailboxes, see Understanding Recipients.

To learn more about managing mailboxes, see Managing User Mailboxes.

Figure 1   Components of a mailbox