A missing event is an event that is supposed to occur within a specified time interval, but does not. If you perform or automate routine tasks such as system backups, Microsoft Operations Manager 2000 (MOM) can generate alerts and responses if these tasks do not occur as planned.
For example, each night, you might run a backup application (BackupApp) that backs up your critical data. The backup should finish successfully between midnight and 6:00 A.M. When this application finishes successfully, it logs a 1001 event in the Application event log. You can create a missing event rule for the 1001 event to show up in the Application event log between midnight and 6:00 A.M. If the 1001 event is not logged during that time, (MOM) can send an alert and respond with a paging notification to a network administrator.