AUTO_CLOSE { ON | OFF }
ON
The database is shut down cleanly and its resources are freed after the last user exits.
The database automatically reopens when a user tries to use the database again. For example, by issuing a USE database_name statement. If the database is shut down cleanly while AUTO_CLOSE is set to ON, the database is not reopened until a user tries to use the database the next time the Database Engine is restarted.
OFF
The database remains open after the last user exits.
The AUTO_CLOSE option is useful for desktop databases because it allows for database files to be managed as regular files. They can be moved, copied to make backups, or even e-mailed to other users.