I was building a new test environment here for ex 2010 (I scrapped the old Hyper-V VM’s & wanted to start from scratch with the RC) and it had been a while since I did an exchange 2010 install. So here I was diving face first into it like i’ve never done it before. I first did the prudent thing and verified the correct pre-req’s were there for the Domain, forest, etc…
     I made a new all 2008 R2 forest. One DC, and two exchange 2010 boxes. I created the forest – upped the domain and forest levels as high as I could, added them to the domain and patched fully. I had recalled the necessary components for the exchange servers themselves, (Powershell 2.0, .net framework 3.51, etc..) and figured by going with 2008 R2 RTM i couldn’t go wrong. Well some of the pre-req were missing, like the office filter and some IIS components for some of the roles. I found the correct link for the office filter
       Office filter
      So then i figured i would just add all the IIS components i could fit and hope for the best. Well that only resulted in an epic fail. There are certain windows 2008 components that need to be installed for most roles. I ran the following command reference from either a powershell 2.0 prompt or the command prompt.
       Add-WindowsFeature NET-Framework,RSAT-ADDS,Web-Server,Web-Basic-Auth,Web-Windows-Auth,Web-Metabase,Web-Net-Ext,Web-Lgcy-Mgmt-Console,WAS-Process-Model,RSAT-Web-Server,Web-ISAPI-Ext,Web-Digest-Auth,Web-Dyn-Compression,NET-HTTP-Activation,RPC-Over-HTTP-Proxy
       This particular string was for a "typical" install on Server 2008 R2. I got this from the following very helpful site.. ex2010 walkthrough of installation
       Once that was complete and my components were installed and the system restarted the install was flawless with zero warnings and errors.