System.Data.SqlClient.SqlError: The backup set holds a backup of a database other than the existing ‘dbName’ database

System.Data.SqlClient.SqlError: The backup set holds a backup of a database other than the existing ‘dbName’ database

Problem
You have backup a database on SQL Server 2005. Then, you try to restore the backup file on an existing database and receive the error message below:

This error message indicates that you are going to restore a database on another database which are not the same database. For example, you have backup Northwind database and try to restore the backup to AdventureWorks database, the error will occur.

Solution
1. To solve the problem, you can use the overwrite the existing database option while you’re restoring.

On Restore Database, select Options tab on the left menu. Then, check Overwrite the existing database on Restore options.
Note: This option will overwrite any existing data on the targeted database.
2. Try to restore the database, the problem should be gone now.
 
Note: you can also delete the targeted database before perform restore a database. This way also gives the result as same as the solution above.