Update that will allow you to install Exchange 2007 SP1 into a Single-label named domains is now available

EDIT: This post was updated on 5/2/2008 to include links to international versions of new XML files.

We're happy to announce the release of the English version of an update to the Exchange Server 2007 SP1 Setup prerequisite check file. This update will allow you to install Exchange 2007 SP1 in a single-label domain (SLD). To read more history behind this, please go here.

Localized versions of this file will be available soon, and we'll update this blog post when they are available. Do not use the English version of the file if you are running a non-English version of Exchange 2007.

There are three scenarios in which this update can be used:

Installation on Internet connected computers:

1. Run Setup (from a file share etc.) and the XML update will be automatically downloaded, installed, and applied. If you are installing from Exchange 2007 SP1 DVD, please see the instructions below.

Installation on non-Internet connected computers:

1. Using an Internet connected computer:

  • Download and extract Exchange 2007 SP1 to a local hard drive.
  • Download and extract the applicable updated ExBPA.PreReqs.xml file listed below. Please note: We suggest that you right-click the link and select "Save target as..." as otherwise the XML file might open in your browser window.
  • Save the file to your local hard drive. Note: Do not make any modifications to ExBPA.PreReqs.xml. Modifying this file will cause it to fail
  • Locate ExBPA.PreReqs.xml which was extracted from the Exchange 2007 SP1 download. The default location is "Setup\ServerRoles\Common\<language>". Rename the original XML file to something else or save it to a different location.
  • Replace the ExBPA.PreReqs.xml file which was extracted from the SP1 download with the updated ExBPA.PreReqs.xml file.

2. Copy the Exchange 2007 SP1 setup files that you have modified to the non-Internet connected Exchange Server which you are trying to upgrade to Exchange 2007 SP1.

3. Run Setup on the non-Internet connected computer by using the files you copied as per above.

If you are installing Exchange 2007 SP1 from the DVD media:

1. Copy the Setup files to the local hard drive. This step is necessary, because if Setup is run from a DVD, it will not check for an updated XML file. This applies to both Internet and non-Internet connected computers.

2. Follow the applicable directions from above, depending on if the computer is connected to the Internet or not.

For more information about the readiness check, see

Exchange Server 2007 SP1 Setup Wizard > Readiness Checks Page


- Ed Beck

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Comments (19)
  1. Eric says:

    Thank you.

  2. Mike Crowley says:

    Thanks!  We really appreciate you listening (and taking action!) to our feedback!

  3. Jesper says:

    Thanks for the update

    – I tried to install Exchange 2007 on our single-label domain 1 day too early…

    I was very happy to see this fix the next morning! (We have about 15 users so this was the production-server I was upgrading…)

  4. Vince says:

    Well I bit the bullet and it bit back! I tried to install SP1 yesterday and things were going well right up to the point where it failed and will not come back. The current error I get is The domain is invalid. No explanations or anything. I’m wondering if there is something in SP1 that doesn’t like the SLD even though it allows the install.

    At this point I’m alomost back up, transport not working. I have a call into MS but I am waiting for a call back this morning. Can’t find anything on the web for it.

    It’s just a great way to start the week :(

  5. alex says:

    How about installing the English Exchange server (with updated ExBPA.PreReqs.xml) on a non-English operating system?

    I still get the error about Single-label Domain Name.

  6. lenny says:

    Well,  I think I have the worst case possible.   AD 2000.  Exchange 2000.  Single Domain Label.

    My client wants to migrate AD 2008 with Exchange 2007.

    My understanding is that I can’t bypass 2003 version if i want to rename the domain name.   Am I wrong?


  7. markus says:

    When do you think will the xml update for other language versions, e.g. German, follow?

  8. Ed Beck says:


    Please wait for the localized versions of the XML file.  I do not have a date on when the localized versions will be available.  As soon as I have more information I’ll post it here

  9. Ed Beck says:


    Your understanding is correct.

    In order to perform the domain rename you’d need Windows Server 2003 and Exchange Server 2003.  Windows did not support domain rename until Windows 2003, and if you were to upgrade to Windows Server 2008 you would not be able to install Exchange 2003, which is the only version of Exchange in which you can use the Exchange Domain Rename Fix-up Tool.

    So yes, if you wanted to rename the domain you’d need to install Windows Server 2003 and Exchange Server 2003, and then rename the domain.  At this point however, if you wanted to further upgrade the operating system to Windows Server 2008 you’d need to remove Exchange Server 2003 since Operating System in-place upgrades of Exchange Servers are not supported (see http://msexchangeteam.com/archive/2007/10/04/447188.aspx for more information).

    Your alternative is to build a new FQDN domain parallel to the existing SLD and then migrate users.

  10. Ed Beck says:


    I do not have a date on when the localized versions will be available.  As soon as I have more information I’ll post it here.

  11. Stive says:

    Hi all

    What about Domain Names with _ in the Name? Ex07 RTM have no problem with this. SP1 let me now that is e error. Is there a Technical Limitation in the Ex07 Setup SP1 that this error maintainable?

    Is it Technical correct that i can change the xml File from


    Name="fDNSDomainNameNotValid" Query="not(matches($., ‘^[A-Za-z0-9-.]*$’))"


    Name="fDNSDomainNameNotValid" Query="not(matches($., ‘^[A-Za-z0-9-._]*$’))"

    Thanks for any Answer

  12. Andy.Hardin says:

    It appears that the string "$’" messes with the e-mail alerts.

  13. Ed Beck says:

    Domain Names with underscores (_) are not supported by Exchange.  Please see Naming conventions in Active Directory for computers, domain, sites and OUs http://support.microsoft.com/?id=909264 for more information.

    Editing ExBPA.PreReqs.xml is not supported.  Modifying this file will cause it to fail.

  14. Ed Beck says:

    We expect the localized versions of the ExBPA Prerequisite rules to be available for download by the first week of May.  When they are available I’ll add a comment to this blog with the announcement and edit the blog to include the links to the localized ExBPA.PreReqs.xml files.

  15. Ed Beck says:

    The localized versions of ExBPA.PreReqs.xml are now available.  The download locations have been added to this blog post in the section entitled "Installation on non-Internet connected computers".  

    Please note: We suggest that you right-click the link and select "Save target as…" as otherwise the XML file might open in your browser window.

  16. Ken says:


    I am having to move from an SLD to FQDN in my organization. I am the planner/organizer and implementer in this operation. There are app. 26 servers to move. About 180 desktops that are in 2 (two) domains. 1 Firewall and 1 DMZ.

    I will have available to start the setup 3 new servers.

    Has anyone started planning a move to a FQDN at this point? If so, I’d like to share the transitional information that I have and compare notes to see how anyone else is doing the move.

    I have not found any articles on how to do a move from SLD to FQDN. Has anyone else?

    Please post a respose here and we’ll figure out a way to get in touch off the blog.



  17. Mark says:

    We are just starting to evaulate whether we need to make the move or not.  We are looking for business reasons why we should and should not move. Anything you have I would value and will share what we have as well.

  18. Ken says:

    Hi Mark,

    business reasons for moving to FQDN; main one being future expansion of the network and being able to stay current with desktop OS and server OS software. As well Exchange has been kind to let us go to SP1 with a single label but I doubt they’ll continue that practice.

    as well I found the following:

    Problems that are associated with single-label namespaces include the following:

    • Single-label DNS names cannot be registered by using an Internet registrar.

    • Domains that have single-label DNS names require additional configuration.

    • The DNS Server service may not be used to locate domain controllers in domains that have single-label DNS names.

    • By default, Windows Server 2003-based domain members, Windows XP-based domain members, and Windows 2000-based domain members do not perform dynamic updates to single-label DNS zones.

  19. Ed Beck says:


    Thank you for a great response.  I can fill in the question about future versions of Exchange.

    Exchange 2007 (and Service Packs for Exchange 2007) is the last version of Exchange that will support Single Label Domains.  The next version of Exchange will block installation if you attempt to install it on an SLD.

    For more information please see the previous post in this series, Single-label Domain Names and Exchange Server 2007 SP1 (Part Deux) at http://msexchangeteam.com/archive/2008/02/15/448140.aspx

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