Upgrading CMS 6 R1 sites compiled against .NET 4.0

If your EPiServer CMS 6 R1 site is compiled against .NET 4.0 or is using components compiled against .NET 4.0 (Caste.Core for example), you will have problems upgrading your site to CMS 6 R2 using Deployment Center.

The problem is that the last step of the upgrade has to run in the context of the site. The way this is done is that Deployment Center starts a new AppDomain and loads the site into it as IIS would. However, by default, Deployment Center runs as a .NET 2.0 application and therefore cannot load a site with .NET 4.0 dependent assemblies.

The workaround is to run Deployment Center as a .NET 4.0 application by adding the following lines to its application configuration file:

<configuration>
   <startup>
      <supportedRuntime version="v4.0"/>
   </startup>
</configuration>

The Deployment Center configuration file can be found at the following path on the target machine:

{Program Files}\EPiServer\Shared\Install\EPiServerInstall.exe.config

Happy upgrading!