Today I inadvertently stumbled into this weird problem. My Visual Studio 2012 couldn’t add new Data Source using EF 6.1.1. After spent my whole morning still unable to get it to work. I resorted to switching back to EF 6.0.0, which works. Anyway, I’ll just put the steps here for those who might be able to solve this mystery.

First, let’s look into my Visual Studio version:

Next, I’ll create a Windows Form project.

Next, I installed EF 6.1.1 through NuGet

Then, I try to add Entity Framework data source in the following steps:

I clicked New Connection button then …BAMM… Exception!

Hoping for clues, I looked into Event Viewer, but I found nothing. I even restarted Visual Studio with logging turned on, but no error logs generated.

UPDATE: I’ve reported this problem in EF’s Codeplex.