Model compatibility cannot be checked because the database does not contain model metadata.

http://digitaltoolfactory.net/blog/2012/03/how-to-fix-the-entity-framework-code-first-problem-model-compatibility-cannot-be-checked-because-the-database-does-not-contain-model-metadata-problem/

USE [master]
GO

/****** Object: Database [MyDBname] Script Date: 02/24/2012 13:54:40 ******/
ALTER DATABASE [MyDBname] SET SINGLE_USER WITH ROLLBACK IMMEDIATE
ALTER DATABASE [MyDBname] SET SINGLE_USER WITH NO_WAIT
DROP DATABASE [MyDBname]
GO