Entity Framework code first migrations throwing error

Question

Here is what I did before I got this error:

1. Installed EF (the pre release version, 6 maybe, I dunno)
2. decided I did not want, so uninstalled that and reins

Answer 1

I figured out the problem. EntityFramework.dll needed to be in the GAC for Visual Studio to use it from the package manager.

1. Start Visual Studio Command Prompt (ensure you started Visual Studio as Administrator)
2. Go to your packages directory and find the EntityFramework package directory.
3. Go to lib\net45 (if targeting 4.5)
4. type: gacutil /i EntityFramework.dll

Note: It may be wise to restart the computer entirely at this point.

I'm not sure why Visual Studio stopped seeing the DLL, but this got me past this problem.