There are a few features that make the All Unity Errors monitored event special.  It cannot be deleted, it is the only event that will trigger notifications from more then one event source.  Based on the version of Unity you have this event will monitor all Cisco Unity component sources.

 

Cannot be deleted - Because of the special handling for this event this event can only be deactivated, not deleted.

Multiple event sources - This event will trigger notification for all errors that came from Cisco Unity components unless that source has been excluded.