No Entity Framework provider found for the ADO.NET provider with invariant name 'System.Data.SqlClient'

I just got into the same problem and it looks like EntityFramework although installed from NuGet Package Manager was not correctly installed in the project.

I managed to fix it by running the following command on Package Manager Console:

PM> Install-Package EntityFramework

You've added EF to a class library project. You also need to add it to the project that references it (your console app, website or whatever).

You don't need to install Entity Framework in your Console application, you just need to add a reference to the assembly EntityFramework.SqlServer.dll. You can copy this assembly from the Class Library project that uses Entity Framework to a LIB folder and add a reference to it.

In summary:

• Class Library application:
  
  • Install Entity Framework
  • Write your data layer code
  • app.config file has all the configuration related to Entity Framework except for the connection string.
• Create a Console, web or desktop application:
  
  • Add a reference to the first project.
  • Add a reference to EntityFramework.SqlServer.dll.
  • app.config/web.config has the connection string (remember that the name of the configuration entry has to be the same as the name of the DbContext class.

I hope it helps.