Lets assume that your database is down, your users are in a panic, what do we do?. If you have been performing routine backups of your database, you can restore it to the point of the most recent backup.

We normally restore a Database when it has been backed up from some other server or from the same server.

Whereas, attaching a Database is like simply including the MS SQL Server file with the .mdf extension and we can start using the database right away.

Make sure you have proper privileges for doing and performing the task and activities that you are doing.