NuGet is causing compatibility issues inside my asp.net mvc project when i try to map my database tables inside .edmx file

I have the following:-

1. Visual studio 2012 professional.
2. Asp.net MVC 4 web application.
3. 2 .EDMX files representing 2 SQL server 2008 r2 databases.

Now my asp.net mvc web application was working well. but today i have applied many updates to one of the sql server databases. and to map the new changes inside the related .edmx file. i did the following usual steps:-

1. i remove the old .edmx file named "model2.edmx" from my visual studio 2012 project.
2. I right click on the Model folder >> add new >> Data >> ADO.net Entity Data model >> i selected the database tables, and click on finish.
3. but during the process of creating the new .edmx file i got this error:-

4. now i use to have 2 .edmx files (model1.edmx &model2.edmx) and under them there is a .tt folder. but now my models look as below (wheremodel1.edmx is the one i did not update), while seems there is 2 folders for the newmodel2.edmx and it does not contain the .tt folder as in model1.edmx..

so can anyone advice how i can recreated model2.edmx  ?? to be similar to the current model1.edmx ?? i am ot sure why nuget which is a feature inside visual studio is raising a problem when i am trying to map my database tables !!