When working with the Entity Framework Code First I will often get the error below:

An exception of type “System.Data.SqlClient.SqlException’ occurred in EntityFramework.dll but was not handled by in user code’

Additional information: Cannot drop database [database name] because it is currently in use.

To force a delete of the database, follow the steps below.

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Figure: This exception is common after you have opened a LocalDb database in Visual Studio.


Open Library Package Manager and Stop the LocalDb instance

a: Select Tools | Library Package manager | Package Manager Console

b: Execute the following two statements

                  sqllocaldb stop v11.0

                  sqllocaldb delete v11.0

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Figure: The steps above will stop and delete the LocalDb instance.


Delete the database file from the database


Figure: Open the Solution Explorer and choose Show All Files

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Figure: Delete the mdf from the App_Data folder