Exchange 2010 SP1 Hosted Installation Failure

Those of you have been playing with Exchange 2010 SP1 Hosted version might have run into some issues during the installation process. Having installed different versions Exchange multiple times you could get caught in the repetition trap, where you install Exchange the same way you have for previous versions.

For the Hosted version of Exchange 2010, extra commands are needed for the installation to succeed. To prepare Active Directory for Exchange 2010 hosting, you must run the following command:

 Setup.com /PrepareAD /Hosting

If you forget to add that "/Hosting" entry and continue to the server install with the following command:

Setup.com /Mode:install /Roles:m,ca,ht /Hosting /on:Exch2010

You will get the following error:


Active Directory wasn't prepared using hosting mode.  To install server roles for hosting mode, you need to clean up Active Directory and prepare it again for hosting mode. 


In order to continue with your Hosted Exchange install you must remove a registry key and remove some objects via ADSI Edit. Locate and then select the following subkey in the registry:


HKEY_LOCAL_MACHINE\Software\Microsoft\ExchangeServer\V14

Delete the PARTNERHOSTEDMODE registry key.


Then go into ADSI Edit expand Default naming context, find and then delete the following two objects:

Microsoft Exchange Security Groups
Microsoft Exchange System Objects

Next expand the Configuration container and delete the following two objects:
      
Microsoft Exchange
Microsoft Exchange Autodiscover

Now you can go back, run the PrepareAD command with the Hosting switch and then proceed to run your server install. Now you can explore Hosted Exchange