title: Error after updgrading from EF 5 to EF 6.0.2
body: <p>After upgrading from EF 5 to EF 6.0.2 I'm getting this error when executing the <code>Update-Database</code> command from the <code>Package Manager Console</code>:</p>
  
  <blockquote>
    <p>Could not load file or assembly 'System.Web.Helpers, Version=3.0.0.0,
    Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its
    dependencies. The system cannot find the file specified.</p>
  </blockquote>
  
  <p>Everything worked just fine before the upgrade.</p>
  
  <p>This is my <code>app.config</code>:</p>
  
  <pre><code>    &lt;configSections&gt;
      &lt;section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" /&gt;
      &lt;!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 --&gt;
    &lt;/configSections&gt;
    &lt;connectionStrings&gt;
      &lt;add name="DefaultConnection" connectionString="Data Source=.;Initial Catalog=aspnet-CodeFirst-Test;Integrated Security=SSPI;" providerName="System.Data.SqlClient" /&gt;
    &lt;/connectionStrings&gt;
    &lt;system.web&gt;
      &lt;roleManager enabled="true" defaultProvider="SimpleRoleProvider"&gt;
        &lt;providers&gt;
          &lt;clear /&gt;
          &lt;add name="SimpleRoleProvider" type="WebMatrix.WebData.SimpleRoleProvider, WebMatrix.WebData" /&gt;
        &lt;/providers&gt;
      &lt;/roleManager&gt;
      &lt;membership defaultProvider="SimpleMembershipProvider"&gt;
        &lt;providers&gt;
          &lt;clear /&gt;
          &lt;add name="SimpleMembershipProvider" type="WebMatrix.WebData.SimpleMembershipProvider, WebMatrix.WebData" /&gt;
        &lt;/providers&gt;
      &lt;/membership&gt;
    &lt;/system.web&gt;
    &lt;runtime&gt;
      &lt;assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1"&gt;
        &lt;qualifyAssembly partialName="WebMatrix.WebData" fullName="WebMatrix.WebData, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" /&gt;
      &lt;/assemblyBinding&gt;
    &lt;/runtime&gt;
    &lt;entityFramework&gt;
      &lt;defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework"&gt;
        &lt;parameters&gt;
          &lt;parameter value="v11.0" /&gt;
        &lt;/parameters&gt;
      &lt;/defaultConnectionFactory&gt;
      &lt;providers&gt;
        &lt;provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" /&gt;
      &lt;/providers&gt;
    &lt;/entityFramework&gt;
    &lt;startup&gt;
      &lt;supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5.1" /&gt;
    &lt;/startup&gt;
  </code></pre>
  
  <p>This is my <code>Configuration.cs</code> file:</p>
  
  <pre><code>public Configuration()
      {
          Database.SetInitializer&lt;DataContext&gt;(new DropCreateDatabaseAlways&lt;DataContext&gt;());
          AutomaticMigrationsEnabled = true;
          AutomaticMigrationDataLossAllowed = true;
      }
  
      protected override void Seed(DataContext context)
      {
          //  This method will be called after migrating to the latest version.
  
          //  You can use the DbSet&lt;T&gt;.AddOrUpdate() helper extension method 
          //  to avoid creating duplicate seed data. E.g.
          //
          //    context.People.AddOrUpdate(
          //      p =&gt; p.FullName,
          //      new Person { FullName = "Andrew Peters" },
          //      new Person { FullName = "Brice Lambson" },
          //      new Person { FullName = "Rowan Miller" }
          //    );
          //
  
          SeedMembership(context);
      }
  </code></pre>
  
  <p>I read that <code>SimpleMembershipProvider</code> got 'replaced' with <code>Identity</code>. Not sure if that is related to this error. But if anyone knows a tutorial how to do the migration, I'd love to have a link of that.</p>
  
  <p>Also the database layer is a <code>class lib</code> project. There is no <code>MVC</code> installed in there.</p>