Domain has an unknown Exchange signature

[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: 2010-04-28

The Microsoft Exchange Best Practices Analyzer queries the Active Directory directory service to determine which version of DomainPrep was last run in the given domain. The version number of DomainPrep acts as the Exchange signature for the domain. The Analyzer tool examines the objectVersion attribute of the given domain's Exchange System Objects object. The following are valid values:

  • For Exchange 2000 Server, the objectVersion value is 4406.

  • For Exchange Server 2003, the objectVersion value is 6936.

  • For Exchange Server 2007, the objectVersion value is 10628

  • For Exchange Server 2007 Service Pack 1 (SP1), the objectVersion value is 11221.

  • For Exchange Server 2010, the objectVersion value is 12639.

  • For Exchange Server 2010 Service Pack 1 (SP1), the objectVersion value is 13040.

If the Analyzer tool does not find one of these listed values for the objectVersion attribute, an error is displayed.

This value is likely to be incorrect if you installed a pre-release version of Exchange 2000 Server or of Exchange Server 2003 in the given domain, but you did not run the released version of DomainPrep.

In Exchange 2000 Server and in Exchange Server 2003, you performed the Active Directory preparation steps by running setup /forestprep and setup /domainprep. Exchange Server 2007 does not have the /forestprep and /domainprep options. For Exchange Server 2007 or for Exchange Server 2010, you run the setup /PrepareDomain process or the Setup Wizard. In either method, you use an account that has the permissions that are required to prepare Active Directory and the domain.

To remedy this error for Exchange 2000 Server or for Exchange Server 2003, run the final release version of Exchange 2000 Server DomainPrep or of Exchange Server 2003 DomainPrep, or run the final released version of the PrepareDomain process or Setup Wizard for Exchange Server 2007 or for Exchange Server 2010. The account that you use to run DomainPrep, to run PrepareDomain, or to run the Setup Wizard must be a member of the Domain Admins security group in the local domain. The account must also be a local computer administrator.

You must run DomainPrep in the following domains:

  • The root domain.

  • All domains that will contain Exchange 2000 Server or Exchange Server 2003 computers.

  • All domains that will contain Exchange 2000 Server or Exchange Server 2003 mailbox-enabled objects (such as users and groups), even if no Exchange servers will be installed in these domains.

  • All domains that will contain global catalog servers that Exchange directory access components may potentially use.

  • All domains that will contain Exchange 2000 Server or Exchange Server 2003 users and groups that you will use to manage your Exchange organization.

  1. Insert the Exchange CD into your CD-ROM drive. You can run DomainPrep on any computer in the domain.

  2. At a command prompt, type <drive>:\setup\i386\setup /DomainPrep, where <drive> is your CD-ROM drive.

  3. On the Welcome to the Microsoft Exchange Installation Wizard page, click Next.

  4. On the License Agreement page, read the agreement. If you agree to the terms, click I agree, and then click Next.

  5. On the Product Identification page, type your 25-digit product key, and then click Next.

  6. On the Component Selection page, ensure that Action is set to DomainPrep. If not, click the drop-down arrow, and then click DomainPrep. Click Next.

  7. On the Completing the Microsoft Exchange Wizard page, click Finish.

For more information about running Exchange Server 2003 DomainPrep, see Exchange Server Deployment Guide (

For more information about running Exchange 2000 Server DomainPrep, see "Microsoft Exchange 2000 Installation and Setup" (

For more information about preparing Active Directory and Domains for Exchange Server 2007, see "How to Prepare Active Directory and Domains" (

For more information about preparing Active Directory and Domains for Exchange Server 2010, see Prepare Active Directory and Domains.