diff --git a/src/schedule/models/schedule_entry.py b/src/schedule/models/schedule_entry.py
index 8ad6a2d9..f862d666 100644
--- a/src/schedule/models/schedule_entry.py
+++ b/src/schedule/models/schedule_entry.py
@@ -1,7 +1,7 @@
 import sys
 from itertools import count
 
-from django.core.validators import MaxValueValidator, MinValueValidator
+from django.core.validators import MaxValueValidator, MinValueValidator, ValidationError
 from django.db import models
 
 import actions
@@ -157,9 +157,11 @@ def __init__(self, *args, **kwargs):
         if self.next_task_time is None:
             self.next_task_time = self.start
 
-        # used by .save to detect whether to reset .next_task_time
+        # used by .save to detect whether to reset .next_task_times
         self.__start = self.start
         self.__interval = self.interval
+        if self.action not in actions.registered_actions:
+            raise ValidationError(self.action + ' does not exist')
 
     def update(self, *args, **kwargs):
         super(ScheduleEntry, self).update(*args, **kwargs)