Error message when you try to remove Exchange 2000 Server from a mailbox server that no longer hosts mailboxes: "One or more users currently use a mailbox store on this server" (924170)

RESOLUTION

To resolve this problem, remove the affected mailbox server entry from the msExchHomeServer attributes in Active Directory. To do this, follow these steps.

Step 1: Determine whether one or more users have the affected server listed as their Exchange home server

Perform a query to determine whether the affected server is listed in the msExchHomeServerName attribute. If the affected server is listed in the msExchHomeServerName attribute for one or more users, you cannot remove Exchange. To perform this query, follow these steps:

1. Start the Active Directory Users and Computers tool. To do this, click Start, point to Programs, point to Microsoft Exchange, and then click Active Directory Users and Computers.
2. In the Active Directory Users and Computers Microsoft Management Console (MMC) snap-in, right-click the domain container, and then click Find.
3. In the Find Users, Contacts, and Groups dialog box, click the Exchange tab, click to select the Show only Exchange recipients check box, and then click Find Now.
4. On the View menu, click Choose Columns.
5. In the Choose Columns dialog box, click Exchange Home Server in the Columns available list, click Add to move this entry to the Columns shown list, and then click OK.
6. Click the Exchange Home Server column to sort the results in the Exchange Home Server column.
7. Determine whether the mailbox server appears in the value or values that are listed in the Exchange Home Server column. The server that appears in this column is the same value that appears in the msExchHomeServerName attribute.

Step 2: Remove the server from the msExchHomeServerName attribute

Warning If you use the ADSI Edit snap-in, the LDP utility, or any other LDAP version 3 client, and you incorrectly modify the attributes of Active Directory objects, you can cause serious problems. These problems may require you to reinstall Microsoft Windows 2000 Server, Microsoft Windows Server 2003, Microsoft Exchange 2000 Server, Microsoft Exchange Server 2003, or both Windows and Exchange. Microsoft cannot guarantee that problems that occur if you incorrectly modify Active Directory object attributes can be solved. Modify these attributes at your own risk.

If you verify that one or more users have the affected mailbox server listed in the msExchHomeServerName attribute, remove the mailbox server from the particular user's msExchHomeServerName attribute. To do this, follow these steps.

Note If you do not require this user account, you can remove the particular user account instead of following these steps:

1. Start the ADSI Edit tool. To do this, click Start, click Run type adsiedit.msc, and then click OK.
   
   Note The ADSI Edit tool is included with the Windows 2000 Server Support Tools. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

   301423 How to install the Windows 2000 Support Tools to a Windows 2000 Server-based computer

2. In the ADSI Edit MMC, expand Domain NC [domaincontroller.example.com], expand DC=example,DC=com, and then expand the container in which the user who has the mailbox server listed in the msExchHomeServerName attribute is located. For example, expand CN=Users.
3. Right-click CN=username, and then click Properties.
4. In CN=username Properties dialog box, click Both in the Select which properties to view list, and then click msExchangeHomeServerName in the Select a property to view list.
5. Click Clear. The LDAP path of the mailbox server appears in the Edit Attribute box.
6. Remove the contents of the Edit Attribute box to make it blank, press SPACEBAR to let the Set button become available, click Set, and then click OK.
7. Follow steps 2c through 2f to modify the msExchHomeServerName attribute for other user accounts that have this mailbox server set. Then, exit the ADSI Edit MMC snap-in.

Note You do not have to modify the msExchHomeServerName attribute for the SystemMailbox {GUID} recipient.