This monitor checks the Auto Close setting for this database. Since this monitor is a part of an overall standards requirement, an alert would be generated if the setting does not meet the specified standard.
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. However when the database is set to AUTOCLOSE = ON, an operation that initiates an automatic database shutdown clears the plan cache for the instance of SQL Server. Clearing the plan cache causes a recompilation of all subsequent execution plans and can cause a sudden, temporary decrease in query performance
Database mirroring requires AUTO_CLOSE OFF.
Autoclose only makes sense were you are sure the application usage pattern will keep the database closed for relatively long periods. Some single-user apps and some multi-tenancy database hosting situations may benefit from AUTO_CLOSE ON. For all other usages, it is generally not a good idea unless you really understand the application behavior and usage patterns
Design / Implementation Note – From the BOL
If the database is not started, properties that the Microsoft SQL Server retrieves by accessing the database directly instead of retrieving the value from metadata will return NULL. That is, if the database has AUTO_CLOSE set to ON, or the database is otherwise offline.
A warning alert will be raised if the Auto Close option does not match the required setting. Out of the box, the monitor is configured to alert when this setting is set to “ON”.
This issue may be resolved by:
Changing the configuration setting for this database to match the expected value.
Overriding the expected value for this unit monitor for this specific database or all databases.
Alternatively, if this monitor is not of concern for this database:
Disabling the monitor using overrides for this specific database or all databases.
Disabling the top-level aggregate configuration monitor using overrides for this specific database or all databases.