What Causes A Typeloadexception On Migrate.exe For Ef6?

I'm trying to run EF's migrate.exe from the command line as part of our build process. This is my actual command: migrate.exe Hydrogen.Data.dll /startupConfigurationFile:..\..\..\H

Solution 1:

I just ran into this today. This can happen when you used the wrong sets of DLL when you run migrate.exe.

In my case, I used the .Net 4.5 version in migrate.exe but compiled my project using .Net 4.0's version.

After changing the dlls the problem went away.