Microsoft SQL Server MSDB Database Recovery

MSDB database restore from backup:
The restore process using SQL Server Management Studio requires a current backup and can be performed by going to properties of the "msdb" database, Tasks > Restore > Database and pointing to the location of backup media.
 
Use DBCC CheckDB for Database repair:
If no backup is available, we can run "DBCC CheckDB" to save the current MSDB database and its contents. The T-SQL commands below check the integrity of the MSDB database, run a soft repair of the MSDB database, and finally a hard repair of the MSDB database:

• MSDB integrity check; is the database free of corruption?

USE Master;
      GO
        ALTER Database MSDB
        SET SINGLE_USER WITH ROLLBACK IMMEDIATE;
        GO
        DBCC CHECKDB (msdb, NOINDEX);
        GO
        ALTER DATABASE MSDB
        SET-MULTI_USER;
        GO

We want to check the line at the bottom of the return window reporting "allocation" and "consistency" errors. A damaged MSDB database reports an error and requires the DBCC CHECKDB commands below to repair.
 

• MSDB T-SQL command for an attempted "soft recovery" with no data loss:

USE Master;
      GO
        ALTER Database MSDB
        SET SINGLE_USER WITH ROLLBACK IMMEDIATE;
        GO
        DBCC CHECKDB (msdb, REPAIR_REBUILD);
        GO
        ALTER DATABASE MSDB
        SET-MULTI_USER;
        GO

After running the command above, run DBCC CheckDB again to see new status of the the the database.

• MSDB T-SQL command for an attempted "hard recovery" with possible data loss:

USE Master;
      GO
        ALTER Database MSDB
        SET SINGLE_USER WITH ROLLBACK IMMEDIATE;
        GO
        DBCC CHECKDB (msdb, REPAIR_ALLOW_DATA_LOSS);
        GO
        ALTER DATABASE MSDB
        SET-MULTI_USER;
        GO

After running the command above, run DBCC CheckDB again to see new status of the the database.

Replace the MSDB database files.
If the MSDB database is corrupt, and DBCC repair options have not worked, we can put a new MSDB database in by replacing the MSDB database files.

When we replace the MSDB database files we lose all information like custom backup jobs, task information, replication, log shipping, and maintenance plan data.

The steps below are used to replace an existing MSDB database with a new default MSDB database.

• Browse to the SQL Server installation directory and go to the "Templates" folder under the "Binn" directory: