The legacyExchangeDN value is missing from this Exchange database

[This topic is intended to address a specific issue called out by the Exchange Server Analyzer Tool. You should apply it only to systems that have had the Exchange Server Analyzer Tool run against them and are experiencing that specific issue. The Exchange Server Analyzer Tool, available as a free download, remotely collects configuration data from each server in the topology and automatically analyzes the data. The resulting report details important configuration issues, potential problems, and nondefault product settings. By following these recommendations, you can achieve better performance, scalability, reliability, and uptime. For more information about the tool or to download the latest versions, see "Microsoft Exchange Analyzers" at]  

Topic Last Modified: 2010-07-26

The Microsoft® Exchange Best Practices Analyzer Tool queries the Active Directory® directory service to determine the value for the legacyExchangeDN attribute for all mailbox store databases on an Exchange Server computer. If the Exchange Server Analyzer does not find a value for the legacyExchangeDN attribute on any mailbox store, an error is displayed.

A missing legacyExchangeDN could be the result of an administrator modifying Active Directory to recover a database in a disaster recovery situation. To resolve this error, you must modify the legacyExchangeDN attribute using an Active Directory editor, such as the LDP (ldp.exe) tool or Active Directory Service Interfaces (ADSI) Edit.

To ensure that the legacyExchangeDN attribute is correct, examine the legacyExchangeDN attribute of the server where this database resides because, being a child object of that server, this database will have the same legacyExchangeDN.

You should also examine other databases on this Exchange server that did not generate this error, because they should have the same legacyExchangeDN. Know that there are several other system objects that also have this attribute. In a situation where the legacyExchangeDN attribute is missing on a database, it is probable that the attribute is also missing on several other system objects. Therefore, if you use LDP or ADSI Edit to add a new legacyExchangeDN value, you will have to do this on all the other system objects also.


If you modify the attributes of Active Directory objects incorrectly when you use ADSI Edit, the LDP tool, or another Lightweight Directory Access Protocol (LDAP) version 3 client, you may cause serious problems. These problems may require that you reinstall Microsoft Windows Server 2003, Exchange Server 2003, or Exchange Server 2007, or both. Modify Active Directory object attributes at your own risk.

To correct this error in Exchange server 2007 or in an earlier version

  1. Open an Active Directory editor, such as ADSI Edit.

  2. Expand Configuration [DomainName], expand, CN=Configuration,DC=DomainName,DC=DomainSuffix.

  3. Expand CN=Services, and then expand CN=Microsoft Exchange.

  4. Expand CN=OrganizationName, expand CN=Administrative Groups, and then expand CN=AdminGroupName.

  5. Expand CN=Servers, expand CN=ServerName, and then expand CN=InformationStore.

  6. Click CN=StorageGroupName.

  7. In the details pane, right-click the mailbox store whose legacyExchangeDN attribute is missing, and then click Properties.

  8. Scroll down to locate legacyExchangeDN, select it, and click Edit.

  9. In the Value field, enter the correct legacyExchangeDN value.

  10. Close the Active Directory editor.

  11. Restart the Exchange Server computer for the change to take effect.

To correct this error in Exchange Server 2010

  1. Start Exchange Management Shell.

  2. At a command prompt, type the following cmdlet, and then press ENTER:
    set-mailboxdatabase <databasename> -rpcclientaccessserver:<cas-or-casarrayname>

For more information about using ADSI Edit to create a new legacyExchangeDN attribute, see Microsoft Knowledge Base article 273863, How to Change the LegacyExchangeDN Attribute in Native Mode with ADSI Edit.