http://blogs.technet.com/b/meamcs/archive/2012/01/17/exchange-2010-sp2-installation.aspxInstalling SP2 is a relatively straightforward stuff and Exchange 2010 SP1 and SP2 servers can co-exist peacefully alongside each other for as long as it takes to roll out SP2. However, it is best practice to run a consistent service pack level acrossen-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)http://blogs.technet.com/b/meamcs/archive/2012/01/17/exchange-2010-sp2-installation.aspx#3499955Thu, 24 May 2012 21:45:59 GMTd5e57398-b9ef-4490-9955-07cbb4e4a80d:3499955Jason<p>You are missing two windows features for the CAS box. &nbsp;ISAPI Filters and ASP.NET. &nbsp;<a rel="nofollow" target="_new" href="http://blogs.technet.com/b/bshukla/archive/2011/12/06/new-pre-requisites-for-exchange-2010-service-pack-2-and-cas-role.aspx">blogs.technet.com/.../new-pre-requisites-for-exchange-2010-service-pack-2-and-cas-role.aspx</a></p> <div style="clear:both;"></div><img src="http://blogs.technet.com/aggbug.aspx?PostID=3499955" width="1" height="1">http://blogs.technet.com/b/meamcs/archive/2012/01/17/exchange-2010-sp2-installation.aspx#3499734Wed, 23 May 2012 19:03:59 GMTd5e57398-b9ef-4490-9955-07cbb4e4a80d:3499734Rip off<p>You should have your own blog</p> <p><a rel="nofollow" target="_new" href="http://thoughtsofanidlemind.wordpress.com/2011/12/05/installing-exchange-2010-sp2/">thoughtsofanidlemind.wordpress.com/.../installing-exchange-2010-sp2</a></p> <div style="clear:both;"></div><img src="http://blogs.technet.com/aggbug.aspx?PostID=3499734" width="1" height="1">