There are few common tasks in SQL server that should work out of the box, but give errors that confuse less experiences developers. Like when you try to restore a backup from another server, you get:

Restore failed for Server ‘.\SQLEXPRESS’.  (Microsoft.SqlServer.SmoExtended)
System.Data.SqlClient.SqlError: The backup set holds a backup of a database other than the existing ‘SomeDb’ database. (Microsoft.SqlServer.Smo)

The solution could not be simpler: you should use WITH REPLACE option of RESTORE command, or in SQL Server Management studio select “Options” page and check “Overwrite the existing database (WITH REPLACE)”