Restoring the master Database
If master is damaged in some way, for example due to media failure, an instance of Microsoft® SQL Server™ may not be able to start if the damage is severe. There are two methods to return master to a usable state:
- Restore from a current backup.
- Rebuild completely using the Rebuild Master utility.
Important Keep a current backup of master. Rebuilding master using the Rebuild Master utility causes all data stored previously in master to be lost permanently. SQL Server will still be able to access other databases.
If an instance of SQL Server can be started because master is accessible, and at least partly usable, it is possible to restore master from a full database backup. However, if an instance of SQL Server cannot be started because of severe damage to master, it is not possible to restore a backup of master immediately because an instance of SQL Server needs to be running to restore any database. The master database first needs to be rebuilt using the Rebuild Master utility, and the current database backup can be restored as normal.