Error message when you try to remove an orphaned mailbox after a failed move operation in Exchange 2003: "The Operation cannot be performed because this mailbox was already reconnected to an existing user"

Consider the following scenario. You move a mailbox to a server that is running Microsoft Exchange Server 2003. The move operation appears to complete successfully. However, Exchange System Manager stops responding. Additionally, you must manually stop the process. In this scenario, there will be two mailboxes on two different stores. Additionally, the user may be connected to the new mailbox. When you try to remove or reconnect the disconnected mailbox, you receive the following error message:

This problem occurs because the orphaned mailbox is still associated with the original user account. This occurs even though the orphaned mailbox appears to be disconnected.

To resolve this problem, use one of the following methods.

Method 1: Remove the orphaned mailbox by using Exchange maintenance

1. Start Exchange System Manager.
2. Locate and then click the mailbox store that you want. For example, to locate the Mailbox Store (My_Server) store, follow these steps:
   1. Expand Administrative Groups, expand First Administrative Group, expand Servers, and then expand My_Server.
   2. Expand First Storage Group, and then click Mailbox Store (My_Server).
3. On the Action menu, click Properties, and then click the Limits tab.
4. Under Deletion settings, type a number that is less than the age of the orphaned mailbox in the Keep deleted mailboxes for (days) box. For a mailbox that is newly orphaned, type 0 (zero).
5. Configure the maintenance schedule. To do this, follow these steps:
   1. Click the Database tab.
   2. In the Maintenance interval box, click Use custom schedule, and then click Customize.
   3. In the list of days, click the current day so that the row for that day is highlighted. This schedules the maintenance for all day.
      
      Note The scheduling of maintenance for all day can be set or removed. To do this, click a day in the list of days.
6. Click OK.
7. Exit Exchange System Manager.
8. Allow for online maintenance to finish. This may take several hours. You will see event ID 1221 logged in the Application log when online maintenance is finished.
9. In Exchange System Manager, use the Run Cleanup Agent on the Mailboxes folder that contains the orphaned mailbox.

Method 2: Remove the orphaned mailbox manually

Note It will take a take a long time to back up to a personal folder (.pst) file if the mailbox is large.

To remove the orphaned mailbox manually, follow these steps:

1. Use the Exchange Server Mailbox Merge Wizard (ExMerge.exe) tool to export the data from the active mailbox to a .pst file. For more information about how to do this, click the following article number to view the article in the Microsoft Knowledge Base:
   327304� How to use the ExMerge tool to upgrade to Exchange 2000 Server or to Exchange Server 2003
2. Remove the Exchange attributes in the Active Directory Users and Computers snap-in. To do this, follow these steps:
   1. Start the Active Directory Users and Computers snap-in.
   2. Expand Domain.Root_Domain, and then click the container that contains the affected user account. For example, click Users.
   3. Right-click the affected user account, and then click Exchange tasks.
   4. On the Available Tasks page, click Remove Exchange Attributes, and then click Next two times.
   5. Click Finish.
3. Remove the orphaned mailbox on the source store. To do this, follow these steps:
   1. On the server that contains the orphaned mailbox, start Exchange System Manager.
   2. Locate and then click the mailbox store that you want. For example, to locate the Mailbox Store (My_Server) store, follow these steps:
      1. Expand Administrative Groups, expand First Administrative Group, expand Servers, and then expand My_Server.
      2. Expand First Storage Group, and then click Mailbox Store (My_Server).
   3. Right-click the mailbox store that you want, and then click Run Cleanup Agent. For example, click Mailbox Store (My_Server), and then click Run Cleanup Agent.
   4. If the orphaned mailbox is still visible in the pane, right-click the mailbox, and then click Purge.
4. Connect the production mailbox on the target store. To do this, follow these steps:
   1. On the server that contains the orphaned mailbox, start Exchange System Manager.
   2. Locate and then click the mailbox store that you want.
   3. Right-click the mailbox store, and then click Run Cleanup Agent.
   4. If it is required, right-click the mailbox, click Reconnect, click the appropriate user in the dialog box that appears, and then click OK.
   5. Exit Exchange System Manager

For more information, click the following article number to view the article in the Microsoft Knowledge Base: