Like Exchange 2007 Service Pack 1, Exchange 2007 Service Pack 2 is a slip-streamed version.

Exchange 2007 Service Pack 2 introduces several new features, but in order to utilize Exchange 2007 SP2, you must perform the following steps:

  1. Extend the Schema
  2. Prepare Active Directory
  3. Install Windows Installer 4.5
  4. Uninstall Interim Updates

Extend the Schema

In order to deploy Exchange 2007 SP2, you must first extend the schema. Depending on your environment's configuration, one of the following scenarios will happen:

  • If your Active Directory environment currently does not have any Exchange Server version deployed, then when you extend the schema, the schema changes included with Exchange 2000 through Exchange 2010 will be deployed in your environment.
  • If your Active Directory environment is currently Exchange 2000 and you are upgrading to Exchange 2007, then when you extend the schema, the schema changes included with Exchange 2003 through Exchange 2010 will be deployed in your environment.
  • If your Active Directory environment is currently Exchange 2003 and you are upgrading to Exchange 2007, then when you extend the schema, the schema changes included with Exchange 2007 through Exchange 2010 will be deployed in your environment.
  • If your Active Directory environment is currently Exchange 2007 and you are upgrading to Exchange 2007 SP2, then when you extend the schema, the Exchange 2010 schema changes will be deployed in your environment.

Question 1: Why is Exchange 2010 listed above?

For those of you that haven't been keeping abreast of the work we are doing in Exchange 2010, Exchange 2007 SP2 is required for coexistence with Exchange 2010. This enables support for coexistence like ensuring Exchange 2010 mailbox Autodiscover requests that are received by CAS2007 are redirected to the appropriate CAS2010 and enabling ActiveSync proxy support between CAS2010 and CAS2007.

Therefore, to minimize the number of times you have to perform a schema extension, we decided to include the Exchange 2010 RTM schema. For those of you that are planning to upgrade your Exchange 2007 environments to Exchange 2010, this will reduce the number of schema extensions you have to perform. Once you extend the schema with Exchange 2007 SP2, you will not have to extend the schema with Exchange 2010 RTM.

However there are direct benefits with deploying the Exchange 2010 schema with Exchange 2007 SP2. One of the new features in Exchange 2007 SP2 is the ability for administrators to control certain settings at the organization level that originally were configured via configuration files; the schema changes have enabled us to move some of these settings now into AD. Expect to hear more about this in a future blog post.

Question 2: How do I extend the schema?

In order to extend the schema you must meet all the pre-requisites:

  1. You must be running the Exchange 2007 setup with a domain account that is a member of the Schema Admins and Enterprise Admins security groups.
  2. The machine on which you run the Exchange 2007 setup schema extension process must be a member of the same domain and Active Directory site as the Schema Master.
  3. The machine on which you run the Exchange 2007 setup schema extension process must be:

a. Windows Server 2003 SP2 with Windows Installer 4.5 installed
b. Windows Server 2008 with Windows Installer 4.5 installed
c. Windows Server 2008 SP2

To extend the schema, you simply run this command from an administrative command line:

setup /PrepareSchema

The rest on : http://msexchangeteam.com/archive/2009/08/28/452209.aspx