Understanding Disconnected Mailboxes

Applies to: Exchange Server 2010

Each mailbox consists of an Active Directory user and the mailbox data stored in the Exchange mailbox database. (The following figure shows the components of a mailbox.) 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's in the mailbox associated with the user account.

Important

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

Components of a mailbox

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

Warning

If you remove a mailbox, the mailbox data 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 disassociate only the mailbox data from the user account, you must disable the mailbox. For detailed instructions, see 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 specified 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.

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 isn't 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 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 (EMC) 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 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 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.

Working with Disconnected Personal Archives

Personal archives become disconnected when they are disabled. Similar to disconnected mailboxes, a disconnected personal archive can be connected by using the Connect-Mailbox cmdlet with the Archive parameter.

The primary mailbox and the personal archive share the same legacy distinguished name (DN), so you must connect the personal archive to the same user mailbox that it was previously connected to. You can't connect the personal archive to a different user mailbox.

There are two operations that you can perform on disconnected personal archives:

• Connect it to an existing mailbox in Active Directory
• Permanently delete it from the Exchange mailbox database

Connecting Disconnected Personal Archives

A disconnected personal archive is retained in the mailbox database for a specified amount of time. By default, Exchange retains the disconnected personal archives for 30 days. During this time, you can recover the personal archive by associating it with an existing mailbox.

Note

If you disable a personal archive for a user mailbox and then enable a personal archive for that same user, that user mailbox will get a new personal archive. You must use the Connect-Mailbox cmdlet to connect a disabled personal archive to an existing mailbox.

Disconnected personal archives won't display in the Disconnected Mailbox node of the EMC. You must the Connect-Mailbox cmdlet in the Shell to reconnect the personal archive. For more information, see Connect a Disconnected Personal Archive.

Permanently Deleting a Disconnected Personal Archive

Exchange retains disconnected personal archives based on the deleted mailbox retention settings configured for the mailbox database. The default retention period is 30 days. After the specified retention period, a disconnected personal archive is permanently deleted from the mailbox database.

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