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

Question

I recently upgraded/updated Entity Framework in an old project from version 4 or 5 to version 6. Now I get this exception:

An exception of type \'Syst

Answer 1

I had the same problem and the only thing that works for my was to uninstall entity framework package from each project using Uninstall-Package. And then intall it again in the whole solution. It will ask you to choose in which project you want to install it, you shall select all.