Today I tested an upgraded on my CRM system running server 2012. I first upgraded CRM Dynamics 2011 to RU15, after that I did a restart.

I ran the upgrade from Server 2012 to Server 2012 R2 (Note that CRM Dynamics 2011 is not supported on Server 2012 R2)

After the upgrade IIS issued an error saying that the WSS service was disabled as the server is running IIS 7.5 and not IIS 7.0.

When I checked my site was gone. No sweat, I navigated to the CRM Dynamics folder under programs files and ran the ServerSetup. It gave me 3 options, I chose repair and pointed to the install files. After it had finished I did an IISReset and navigated to the CRM URL only to be met with the following error:

“HTTP Error 500.19 – Internal Server Error

The requested page cannot be accessed because the related configuration
data for the page is invalid.

`Detailed Error Information`
Module IIS Web Core
Notification Unknown
Handler Not yet determined
Error Code 0x8007000d
Config Error
Config File \?C:wwwrootweb.config
Requested URL http://localhost:80/Default.aspx
Physical Path
Logon Method Not yet determined
Logon User Not yet determined
Config Source

Quick check, IIS 7.0 uses the URL Rewrite Module and IIS 7.5 does not. I downloaded the file ( and ran the install, did an IIS reset and went back and CRM Dynamics 2011 was now running fully on Windows Server 2012 R2. 

Hope it helps.