Attempt by security transparent method 'WebMatrix.WebData.PreApplicationStartCode.Start()'

Question

For me this error was because I did NOT have Microsoft.AspNet.WebHelpers installed after updating from MVC 4 to MVC 5. It was fixed by installing the NuGet package

Install-Package -Id  Microsoft.AspNet.WebHelpers

If you are getting the error

Attempt by security transparent method ‘WebMatrix.WebData.PreApplicationStartCode.Start()’ to access security critical method ‘System.Web.WebPages.Razor.WebPageRazorHost.AddGlobalImport(System.String)’ failed.

In order to fix this install this package using NuGet package manager.

Install-Package Microsoft.AspNet.WebHelpers

After that , probably you will get another error

Cannot load WebMatrix.Data version 3.0.0.0 assembly

to fix this install this package using NuGet package manager.

Install-Package Microsoft.AspNet.WebPages.Data

For anyone landing here who is trying to upgrade from MVC 4 to MVC5, I was able to resolve this issue by following the instructions at http://www.asp.net/mvc/tutorials/mvc-5/how-to-upgrade-an-aspnet-mvc-4-and-web-api-project-to-aspnet-mvc-5-and-web-api-2.

I also had to install the "Microsoft.AspNet.WebApi.WebHost" package from nuget. But that's it.

Oh, and I had to create this appSetting: <add key="owin:AutomaticAppStartup" value="false" />

:)

I tried all of the above solutions and it still wouldn't work, until I found that the web.config compilation element was referencing version 2.0.0.0 of WebMatrix.Data and WebMatrix.WebData. Changing the version of those entries in the web.config to 3.0.0.0 helped me.

I've been struggling with a similar issue when upgrading mvc 4 to mvc 5:

Attempt by security transparent method 'System.Web.WebPages.Administration.SiteAdmin.RegisterAdminModule()' to access security critical method 'System.Web.WebPages.ApplicationPart..ctor(System.Reflection.Assembly, System.String)' failed.

The delete extra files check box in the publish dialog solved it for me.

Reinstalling Microsoft.AspNet.WebHelpers works for me

Update-Package –reinstall Microsoft.AspNet.WebHelpers