Disconnect mailboxes are the mailbox objects which are no longer associated with Active Directory user account and are purged automatically when the default time period (30 days) is over. If the need arises, Exchange administrators have the option to reconnect the disconnected mailbox, but only within the retention period.

As depicted in the above image, connectivity between Active Directory and user mailbox is no longer available and results in disconnected mailboxes. In both instances of disconnected mailboxes – disabling mailboxes and soft deletion, administrators can reconnect the disconnected mailboxes.

How Exchange Administrators can reconnect mailboxes?

The following methods help in reconnecting the disconnected mailbox in Exchange server:

1. Reconnect deleted mailboxes to same user account
2. Restore disabled mailboxes to same user account
3. Create a different user account that isn’t mail-enabled and doesn’t have a mailbox
4. Use software to reconnect

Method 1. Reconnect deleted mailbox to same user account

1. Use Connect-Mailbox cmdlet: Use Exchange Administration Center (EAC) or Exchange Management Shell (EMC) to connect to original Active Directory user account
2. Use New-MailboxRestoreRequest: Reconnect with the help of PowerShell cmdlet

Check that the administrator has all the permissions to reconnect the disconnected mailbox:

1. Check whether you have the right to open the Exchange Administration Center or EAC. Click the link for validation.
2. Check if you have the rights to open Exchange Management Shell. Click the link to validate.
3. Check that the Active Directory user account that you want to reconnect exists and not associated with another mailbox. To verify, run the cmdlet – Get-User
4. Replace <Display Name> with the display name of the mailbox and run the command:

$dbs = Get-MailboxDatabase

$dbs | foreach {Get-MailboxStatistics -Database $_.DistinguishedName} | where {$_.DisplayName -eq “<DisplayName>”} | Format-List DisplayName,Database,DisconnectReason

This checks the user account to which the mailbox is connected to is not linked to any other mailbox database.  Mailbox has to exist in the mailbox database and ‘DisconnectReason’ property should be disabled. In case, a mailbox is purged from the database, there are no results for the command.

5. Check for the assigned permissions before reconnecting the mailbox. Refer Recipient Provisioning Permissions in the recipient Provisioning Permissions topic.

Use Exchange Administration Center or Exchange Management Shell to reconnect user mailboxes

    a. Using Exchange Administration Center to connect mailboxes:

This method helps to connect disabled linked mailboxes and disabled shared mailboxes to the corresponding user account:

• In the EAC, navigate to Recipients> Mailboxes.
• Click More, and then click Connect a mailbox.

EAC displays a list of disconnected mailboxes on the Exchange server. This list comprises disabled mailboxes, deleted mailboxes, and soft-deleted mailboxes

• Click the disabled mailbox to reconnect, and click Connect.
• A window is displayed asking for confirmation. Click Yes.

EAC displays a list of user accounts that aren’t mail-enabled.

• Click the user to connect to deleted mailbox and click OK

Exchange will connect the deleted mailbox to the user account.

b. Using Exchange Management Shell to connect mailboxes

You can also reconnect the disconnected mailbox through the Connect-Mailbox cmdlet in a Shell. Specify the mailbox to be connected- user, linked, room, equipment, and shared mailboxes. Also, in all mailboxes, it is necessary to specify the alias parameter. This is the portion of the email address on the left side of the ‘@’ symbol.

Note: Disable the Active Directory user account that is linked to the mailbox when you are linking resource, linked or shared mailbox.

All types of mailboxes need different commands to reconnect. For example, linked mailboxes with identity parameter connect through the following command:

Connect-Mailbox -Identity “Temp User” -Database ExDB02 -LinkedDomainController AbcDC01 -LinkedMasterAccount sanpark@abc.com -Alias spark

Similarly, commands change for room, equipment and shared commands.

The next step is to verify that the mailbox is reconnected.

The verification steps for EAC and EMC are different. The following command helps in verification:

• For EAC, go to Exchange Administration Center and click Recipients, navigate to the connected mailbox, click Refresh, and verify that the mailbox available.
• In Active Directory Users and Computers, right-click the connected user account, and click Properties. Go to the General tab, and check that the E-mail box is populated with the email address.

For Shell, run the following command:

Type PowerShell cmdlet – Get-User <identity>

• The UserMailboxvalue for the RecipientType property indicates that the user account and the mailbox are connected. Alternatively, run the Get-Mailbox <identity> command to verify mailbox connectivity.

Method 2: Restore Disabled Mailboxes to Same User Account

Exchange Administration Center doesn’t provide an option for restoring. Such mailboxes are reconnected through PowerShell script New-MailboxRestoreRequest.

In Shell, users can use Get-MailboxStatistics cmdlet to display the values of DisplayName, MailboxGuild, and LegacyDN properties for the deleted mailbox that you want to restore.

Method 3: Create a different user account that isn’t mail enabled and doesn’t have a mailbox

Go to Active Directory and create a new mailbox account. This user account should have the same address as the mailbox.

This mailbox account must not be mail-enabled and should not have a mailbox.

Method 4: Use a software to reconnect disconnected mailbox

Exchange Database Recovery Software such as Stellar Repair for Exchange helps in reconnecting the disconnected Exchange mailbox:

1. Select EDB file and click Repair
2. Verify that the mailbox is available in the repaired EDB file and check the mailbox content
3. Select Save and the software provides an option to map the mailbox with the available mailboxes on the Active Directory. Select the mailbox name to reconnect.
4. Selected mailbox is reconnected to a specified mailbox in the Active Directory

Note: Stellar Repair for Exchange also provides an option to create a new account in Active Directory and map the mailbox content with the newly created account.

Restrictions with using EAC and EMC

• Using Exchange Management Shell or Exchange Administration requires reconnecting and verifying the user account, and both processes involve multiple steps.
• User must have all the permissions to work on EMC and EAC.
• Complex steps may not result in desired results
• Time is important: both processes is time taking and require practical knowledge

Restrictions on creating a different user account

• Creating a new user account in Active Directory may not essentially connect the mailbox.
• Active Directory may not allow creating a mailbox with the same name as the one deleted.
• Unmatched names of Active Directory and user mailbox may not result in exact pairing.

Using a software eases the process of reconnecting the disconnected mailbox in the Exchange server and ensures 100% connectivity. It doesn’t require any permissions for usage except that the server admin has Exchange credentials.

Conclusion

There are several technicalities involved in reconnecting mailbox such as using an EAC or the connect-mailbox cmdlet, New-MailboxRestoreRequest, Mailbox Replication Service (MRS) to restore a disconnected mailbox.

In addition, the Exchange Administrator has to consider the time and efficiency factors involved in reconnecting the mailbox. For example, it may take longer to reconnect a disconnected mailbox when the connect-mailbox cmdlet doesn’t work and Administrator has to try the next option i.e., New-MailboxRestoreRequest.

Using software connects the mailbox data to the active directory and administrators can easily avoid the complex manual steps. Also using the software doesn’t require a complex verification process. The software provides the preview of reconnected mailbox data for verification.

Author: Pankaj Bhardwaj

Pankaj is a technical expert at @Stellar addressing several data loss scenarios on Mac & Windows Operating system. He loves to explore new places and learn more about new technologies.