It is quite confusing for people who touch with Entity Framework the first time.

If you use Code First, an mdf file is generated at %USERPROFILE% (e.g. C:\Users\<username> ).

If you use Database First, you create a database under SQL Server Object Explorer (not Server Explorer!), an mdf file will be generated at %LOCALAPPDATA%\Microsoft\Microsoft SQL Server Local DB\Instances\MSSQLLocalDB .

By default, LocalDB database creates “*.mdf” files in the C:/Users/"username" directory.

Link ref: https://docs.asp.net/en/latest/tutorials/first-mvc-app/working-with-sql.html

In SQL Server Management Studio, Right click on DataBase -> Properties -> Files will tell you where on your hard disk it lives. If you backup the mdf, be sure to back up the ldf too.

Alternatively, you can right click on the DB, and choose Tasks -> Backup . This will make a a single .bak file for you, and you don't need to worry about the mdf/ldf.

http://technet.microsoft.com/en-us/library/hh510202.aspx
The system database files for the database are stored in the users' local AppData path which is normally hidden. For example C:\Users--user--\AppData\Local\Microsoft\Microsoft SQL Server Local DB\Instances\LocalDBApp1. User database files are stored where the user designates, typically somewhere in the C:\Users\Documents\ folder.

Try this one -

DECLARE 
      @SQL NVARCHAR(1000)
    , @DB_NAME NVARCHAR(100) = 'AdventureWorks2008R2'

SELECT TOP 1 @SQL = '
    BACKUP DATABASE [' + @DB_NAME + '] 
    TO DISK = ''' + REPLACE(mf.physical_name, '.mdf', '.bak') + ''''
FROM sys.master_files mf
WHERE mf.[type] = 0
    AND mf.database_id = DB_ID(@DB_NAME)

PRINT @SQL
EXEC sys.sp_executesql @SQL

Output -

BACKUP DATABASE [AdventureWorks2008R2] 
TO DISK = 'D:\DATABASE\SQL2012\AdventureWorks2008R2.bak'

Open Windows registry editor and navigate to key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server Local DB\Installed Versions . Look beneath the version key of the SQL Server instance being targeted e.g. 11.0 for SQL 2012, and see its InstanceAPIPath value for file system location of the localdb's.

Note that at full list of SQL server versions mapped to release name and year can be found here

This PowerShell script, will give you the default location for localdb .mdf files:

[System.Reflection.Assembly]::LoadWithPartialName('Microsoft.SqlServer.SMO') | out-null
(New-Object Microsoft.SqlServer.Management.Smo.Server("(localdb)\$instancename")).DefaultFile

where $instancename is the name of the localdb instance you want to check for. You can get a list of localdb instances by running

sqllocaldb i

I tried everything here and could not find them anywhere. I finally found them by searching *.mdf in file explorer. They were in C:\Users\user\source\repos\CallNote\App_Data .