Cannot attach the file *.mdf as database

Take a look at this: Entity Framework don't create database

I would try giving the database a different name. Sometimes you can run into problems with SQL Express when trying to create a database with the same name a second time. There is a way to fix this using SQL Server Management Studio but it's generally easier to just use a different database name.

Edit This answer was accepted because it confirms the bug and the workaround used by OP (renaming database could help). I totally agree that renaming the database is not really an acceptable way, and does not totally solve the issue. Unfortunatly I didn't check the other ways to really solve it in SSMS.

1. From Package Manager Console run:

   sqllocaldb.exe stop v11.0

   sqllocaldb.exe delete v11.0

2. Run your project

3. Register a user

Remove this line from the connection string that should do it ;) "AttachDbFilename=|DataDirectory|whateverurdatabasenameis-xxxxxxxxxx.mdf"

I think that for SQL Server Local Db you shouldn't use the Initial Catalog property. I suggest to use:

<add name="DefaultConnection" 
     connectionString="Data Source=(LocalDb)\v11.0;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\OdeToFoodDb.mdf" 
     providerName="System.Data.SqlClient" />

I think that local db doesn't support multiple database on the same mdf file so specify an initial catalog is not supported (or not well supported and I have some strange errors).