SQL Server Database Marked Suspect Error

For example, when a user attempts to connect to the SQL database and opens SSMS, he encounters this below error message:

"Database 'msdb' cannot be opened. It has been marked suspect"

The main cause of the above error message is that the SQL database has been suspected. This situation occurs under following conditions:

• When the error log file does not match with the database file
• SQL database corruption

When the user views the SQL Server application event log, he finds the following entry:

"The log scan number (152:284:1) passed to log scan in database 'msdb' is not valid. This error may indicate data corruption or that the log file (.ldf) does not match the data file (.mdf). If this error occurred during replication, re-create the publication. Otherwise, restore from backup if the problem results in a failure during startup."