The type initializer for 'System.Data.Entity.Internal.AppConfig' threw an exception

Question

I\'m working with EF5 in a MVC 4 aspnet website. Locally, everything works just fine, but when I publish it to the IIS and try to enter, I get the error

Answer 1

in my case

<section name="entityFramework"

must be updated from version 4 to 6. I mean a project was updated EntityFramework from 4 to 6 but web.config was not updated.

Answer 2

If you are maintaining one more cinfiguration file for app.config , Don't include any key in parent page.

Parent Page : app.config

<appSettings configSource="appSettings.config">
    <add key="ClientSettings" value="venice" /> <!-- Don't add Key Here -->
</appSettings>

Child Page : appSettings.config

<appSettings>
  <add key="ClientSettings" value="venice"/> <!-- add Here -->
</appSettings>

Answer 3

I had same problem. After one day, I got it.

Problem was from adding two smtp tags in mailSettings under <system.net>.

Answer 4

I needed to change by defaultConnectionFactory to be SqlConnectionFactory instead of the default

<entityFramework>
  <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework">
    <parameters>
      <parameter value="<My Connection String>" />
    </parameters>
  </defaultConnectionFactory>
</entityFramework>

http://blogs.msdn.com/b/davidobando/archive/2012/08/14/changing-ef-s-default-provider-from-localdb-to-sql-server.aspx

Answer 5

Do the following in the App.config file,

1. Put the connectionStrings element is after the configSections element.
2. Put the startup element after the connectionStrings element.

<?xml version="1.0" encoding="utf-8"?>
 <configuration>
   <configSections>
         <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=4.3.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
   </configSections>
   <connectionStrings>
         <add name="SchedulingContext" connectionString="Data Source=XXX\SQL2008R2DEV;Initial Catalog=YYY;Persist Security Info=True;User ID=sa;Password=XXX"   providerName="System.Data.SqlClient"/>
   </connectionStrings>
   <startup>
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
  </startup>       
 </configuration>

Answer 6

If you use ASP.NET and IISExpress go to "C:\Users\\Documents\IISExpress\config\applicationhost.config", search for your Project and look if you have a faulty virtualDirectory entry.