DotNetNuke 7 upgrade issues - RESOLVED

I managed to troubleshoot my DNN7 upgrade and hopefully this note will save others some trouble.

Situation: You have installed DNN from the Web App Gallery and you are ready to upgrade to version 7.0. You've done the upgrade several times on a local server without issues and now it's time to upgrade on DiscountASP server.

After ftp'ing the upgrade files you attempt to initiate the upgrade via http://www.<yoursite>.com/install/install.aspx?mode=upgrade and it fails!

Edit the web.config for CustomErrors="Off" and you see:

Could not load file or assembly 'System.Web.WebPages, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

Stack trace info looks something like:

[FileLoadException: Could not load file or assembly 'System.Web.WebPages, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)]
System.Web.WebPages.Administration.SiteAdmin.RegisterAdminModule() +0
System.Web.WebPages.Administration.PreApplicationStartCode.Start() +22

[InvalidOperationException: The pre-application start initialization method Start on type System.Web.WebPages.Administration.PreApplicationStartCode threw an exception with the following error message: Could not load file or assembly 'System.Web.WebPages, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040).]
System.Web.Compilation.BuildManager.InvokePreStartInitMethods(ICollection`1 methods) +423
System.Web.Compilation.BuildManager.CallPreStartInitMethods() +306
System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException) +677

[HttpException (0x80004005): The pre-application start initialization method Start on type System.Web.WebPages.Administration.PreApplicationStartCode threw an exception with the following error message: Could not load file or assembly 'System.Web.WebPages, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040).]
System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +9090876
System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +97
System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +256

I was unable to determine exactly what is referencing an older System.Web.Webpages assembly, but no matter!

The workaround I used was to add bindingRedirect statements as shown below:

<!-- ************************************************************** -->
<!-- START DNN7 upgrade failure workaround -->
<!-- ************************************************************** -->
<!-- ** be sure these are in the section for ** -->
<!-- ** assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1 ** -->
<!-- ************************************************************** -->
<dependentAssembly>
<assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35" />
<bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="2.0.0.0" />
</dependentAssembly>
<dependentAssembly>
<assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />
<bindingRedirect oldVersion="1.0.0.0-4.0.0.0" newVersion="4.0.0.0" />
</dependentAssembly>
<dependentAssembly>
<assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" />
<bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="2.0.0.0" />
</dependentAssembly>
<!-- ************************************************************** -->
<!-- END DNN7 upgrade failure workaround -->
<!-- ************************************************************** -->

This will probably come back to bite me at some point, but its an effective workaround for now.

Good Luck,
David