The system is sending an email "smartd_daemon is not running" because t There is a delay in which the smartd process starts
This is seen in FreeNAS 11.2-U3 Pre-Release
Because there is a delay in which the smartd process starts, an email alert is generated and sent to the customer.
Eventually the smartd process starts and the the alert is removed from the GUI.
My suggestion is to fix this so an email isn't sent to avoid unnecessary reports/complaints