How to Restore Disconnected Mailbox in Exchange Server?

Eric Simson | Updated on February 8, 2024 Exchange Server Recovery

Summary: In this post, we have discussed disconnected mailboxes in the Exchange server and the methods to restore or connect them to a new or existing Active Directory user account. We’ve also mentioned an Exchange recovery software that can help in restoring the deleted and disconnected mailboxes in Exchange Server 2003, 2007, 2010, 2013, 2016, and 2019.

A disconnected mailbox in Exchange Server refers to a mailbox that is not connected to an Active Directory user account. When a user account is deleted from the Active Directory, the connected mailbox is not deleted. Instead, Exchange Server retains it in the database in the disconnected and disabled state.

The disconnected mailbox remains in the database till the retention period is over, which is 30 days by default. After the retention period ends, the disconnected mailbox is automatically purged (permanently deleted) from the database leaving white space.

However, you can restore a disconnected mailbox in Exchange Server to a new or existing AD user before the retention period is over. For this, you can use the Exchange Admin Center (EAC) or PowerShell cmdlet in the Exchange Management Shell (EMS).

Alternatively, you may also convert the disconnected mailbox to a linked mailbox and associate it with an AD user account that exists outside the forest (in a different Exchange Server).

In this post, we have discussed the methods with stepwise instructions to restore disconnected mailboxes in Microsoft Exchange Server and access the mailbox via Outlook client or web app (OWA).

Methods to Restore Disconnected Mailbox in Exchange Server

Below are the methods to restore or reconnect disconnected mailboxes in Exchange Server.

Note: Disconnected mailboxes include disabled mailboxes, deleted mailboxes, and soft-deleted mailboxes.

Method 1: Use Exchange Administrative Center (EAC)

This method helps you restore disconnected or disabled mailboxes in the Exchange Server by reconnecting it to a new AD user account. Make sure you have created an AD user account before proceeding.

Open the EAC and sign in using admin credentials.
In the EAC, go to Recipients > Mailboxes.
Click on More…. and then choose the Connect a mailbox option.

This option lists all the disconnected mailboxes in the Exchange Server.
Click on the disconnected mailbox you want to restore and then click on the Connect button.
Click on the Yes, connect to the user account above option to connect the mailbox to the user if the user exists. Otherwise, choose No, I want to connect to a different user account to connect mailbox to a new AD user account in the window that enquires whether you are sure about reconnecting the mailbox.

If you click the Yes option, the mailbox will be restored to the existing mailbox if the AD user still exists. Otherwise, you might encounter an error.
If you click the No option and then select the new AD user account from the list to connect, the mailbox will be restored to the new user.

Once the mailbox is restored to an existing or new user AD account, the mailbox and its contents can be accessed via Outlook client or OWA.

Method 2: Using Exchange Management Shell (EMS)

You may also use Exchange Management Shell or EMS to connect and restore a disabled or disconnected mailbox in Exchange Server to a user account. For this, you can use the following PowerShell cmdlets.

Connect-Mailbox cmdlet
New-MailboxRestoreRequest cmdlet

Before You Begin

You need to have the Disaster Recovery role assigned to use the New-MailboxRestoreRequest cmdlet and Mail-recipient roles for using the Connect-Mailbox cmdlet. Refer to the below image for more details.

Verify that the Exchange disconnected mailbox that you want to connect to a user account is present in the mailbox database and is not a mailbox that has been permanently deleted.

Reconnect Exchange Mailbox using the Connect-Mailbox Cmdlet

You need to specify the mailbox, database, and user details to reconnect the mailbox in the Exchange. The commands for reconnecting the ‘user’, ‘linked’, and ‘shared’ mailboxes are as follows:

Command to connect a ‘user mailbox’

Connect-Mailbox -Identity "John" -Database RDB01 -User "John"

Here, the parameters ‘Identity’ and ‘User’ specify the disconnected mailbox in the Exchange database and Active Directory user account, respectively, to reconnect the mailbox.

Command to connect a ‘linked mailbox’

Connect-Mailbox -Identity "John" -Database RDB01 -LinkedDomainController STELLARINFODC01 -LinkedMasterAccount john@stellarinfo.com -Alias john

Here, the ‘Identity’, ‘LinkedMasterAccount’, and ‘Alias’ parameters specify the following:

The disconnected mailbox in the Exchange database.
Active Directory user account in the account forest that you wish to reconnect the mailbox.
Alias is a part of the email address.

Command to connect a ‘shared mailbox’

Connect-Mailbox -Identity "My Shared Mailbox" -Database "Database 01" -User "My Shared Mailbox" -Alias myShared -Shared

Note: If the Alias parameter is not included when the Connect-Mailbox cmdlet is executed, the value specified in the ‘User’ or ‘LinkedMasterAccount’ parameter is used to create the email address Alias for the reconnected mailbox.

Use New-MailboxRestoreRequest Cmdlet

This method restores or recovers disconnected mailboxes by merging the data of the disabled mailbox with an existing mailbox. The New-MailboxRestoreRequest cmdlet uses Mailbox Replication Service (MRS) to restore the mailbox of the Exchange Server.

Now, to create a mailbox restore request, you have to use the display name, legacy distinguished name (DN), or mailbox GUID of the mailbox that has been deleted. To display the values of DisplayName, LegacyDN, and MailboxGuid properties for the deleted mailbox to be restored, you need to use the Get-MailboxStatistics cmdlet.

For instance, to get this information for all disabled, deleted, or disconnected mailboxes in your organization, you can run the below command:

Get-MailboxDatabase | Get-MailboxStatistics | Where {$_.DisconnectReason -eq “Disabled”} | Format-List DisplayName, MailboxGuid, LegacyDN, Database

To reconnect and restore the Exchange mailbox, copy the MailboxGuid on the database and run the following command.

New-MailboxRestoreRequest -SourceDatabase "EXDB01" -SourceStoreMailbox ed258566f7-fd75-9631-94e2-4245re393eed -TargetMailbox “Debra Garcia” -AllowLegacyDNMismatch

Note: Remember to replace -SourceDatabase name and MailboxGuid in the -sourceStoreMailbox parameter from the above command.

What does this Command do?

The above command will restore the deleted mailbox to the target mailbox ‘Debra Garcia.’ Here, the deleted mailbox that was located on the EXDB01 mailbox database is identified by the ‘-SourceStoreMailbox’ parameter. The ‘-AllowLegacyDNMismatch’ parameter is used to restore the source mailbox to a different mailbox. The mailbox does not have a legacy DN value that is same.

How to Check if this is Successful?

To verify if the disabled mailbox is successfully connected to the user account, do the following checks:

Via Exchange Admin Center (EAC)

Sign in to EAC and click Recipients.
Navigate to the page that lists the mailbox that you reconnected and click Refresh.
Check if the mailbox is listed.

Via Active Directory (AD)

In Active Directory Users and Computers, right-click on the username whose mailbox was disabled or disconnected.
Choose Properties.
Under the General tab, check if the E-mail box contains the email address of the reconnected mailbox.

Via Exchange Management Shell

Run the following command to check if the mailbox is reconnected and restored:

Get-User “<Identity>”

If the output displays the UserMailbox value for the RecipientType property, it indicates that the user account and the mailbox are connected. Further, you can run the Get-Mailbox cmdlet to verify the mailbox.

Method 3: Use Windows Server Backup

If you create regular backups using Windows Server Backup (WSB), you can restore Exchange mailboxes with the help of this backup tool. Backups help you restore and reconnect deleted mailboxes even if the retention period is expired.

Method 4: Use Exchange Recovery Software

You can use an Exchange repair and recovery software which makes the mailbox restore process easy, especially if you need to restore or recover multiple disconnected mailboxes in Exchange Server. Also, when the mailbox is corrupt or fails to reconnect and restore via the above-mentioned methods.

Stellar Repair for Exchange is an easy-to-use Exchange mailbox recovery software. It can even repair corrupt mailbox and export it to a live Exchange Server or Office 365 directly. You can also,

Repair corrupt EDB files and save the mailbox data as MS Outlook PST file.
Export restored mailboxes to Live Exchange Server or Office 365.
Search specific emails in the repaired EDB database file of the Exchange Server.
Save Exchange mailboxes data in different file formats, such as PST, MSG, EML, RTF, HTML, and PDF.

The software supports Exchange Server 2019, 2016, 2013, 2010, 2007, and up to 5.5.

Rating by MVP:

Conclusion

In this post, we’ve mentioned various methods to restore or reconnect disconnected mailboxes in the Exchange Server. Use the first three methods when the mailbox is deleted but still in the retention period or disabled and disconnected accidentally.

But if the mailbox is corrupt or not restored even after applying these methods, use an Exchange repair tool such as Stellar Repair for Exchange. You can also use the software if you need to restore multiple disconnected mailboxes in Exchange Server.

The software can help you restore deleted or disabled mailboxes from a healthy or corrupt database. It can fix corrupt mailboxes and export the mailbox directly to the Exchange users’ account at up to 4x speed. All you need is valid credentials of the user account on the live Exchange Server and permission to access the user’s mailbox.