“[ERROR] The Client Access server role is already installed on this computer.”

For each rolle that I had installed on said server. I didn’t know why it was doing this. I suspected that ESXi left some reminents of the Exchange Install and that VMWare ESXi Snapshots weren’t really “Snapshots”. So I did a full re-install and still was receiving the above message.

I think starting doing some research and found out that there is Active Directory information that states what roles a server has, and the setup checks this before installing. All I had to do was delete this information. Here is the steps, that I found on the web.

1. Click Start, point to Programs, point to Windows 2000 Support
Tools, point to Tools, and then click ADSI Edit.
2. Expand each of the following items:
Configuration Container
CN=3DConfiguration, DC=3DDomain_Name,DC=3Dcom
CN=3DServices
CN=3DMicrosoft Exchange
CN=3DYour_Organization_Name
CN=3DAdministrative Groups
CN=3DYour_Administrative_Group_Name_Or_Exchange5.5_Site_Name
CN=3DServers

Note In this procedure, Domain_Name is a placeholder for the name of
your domain, Your_Organization_Name is a placeholder for the name of
your organization, and
Your_Administrative_Group_Name_Or_Exchange5.5_Site_Name is a
placeholder for the name of your administrative group or Exchange 5.5
site.
3. Right-click the Exchange 2003 server object, and then click
Delete.
4. Click Yes in every adsiedit dialog box that prompts you to confirm
the deletion.

Once I completed this, I was able to install Exchange 2007 again. I had to process this on the Domain Controller which is a separate machine.