On the Search Alert tab, there is is an "Events Per email" field that limits the number of event that can be sent in a single alert email. A number up to 1,999,999,999 can be specified. If you specify a high value (999,999,999 for example), he Coordinator fails to send the alert and the following is recorded in the Coordinator log:
[ERROR][ChangeAuditor.Coordinator.AlertProcessorSmtpTask._ProcessAllSmtpAlerts(0)] Error processing alert All Active Directory Events (0f8b0a8d-1b51-4f9a-91f5-bbe5f91deaaf): Array dimensions exceeded supported range.
System.OutOfMemoryException: Array dimensions exceeded supported range.