diff --git a/mayan/apps/converter/models.py b/mayan/apps/converter/models.py
index df52ad6747..e58c763426 100644
--- a/mayan/apps/converter/models.py
+++ b/mayan/apps/converter/models.py
@@ -38,7 +38,9 @@ class Transformation(models.Model):
 
     def save(self, *args, **kwargs):
         if not self.order:
-            self.order = Transformation.objects.filter(content_type=self.content_type, object_id=self.object_id).aggregate(Max('order'))['order__max'] + 1
+            last_order = Transformation.objects.filter(content_type=self.content_type, object_id=self.object_id).aggregate(Max('order'))['order__max']
+            if last_order is not None:
+                self.order = last_order + 1
         super(Transformation, self).save(*args, **kwargs)
 
     class Meta:
diff --git a/mayan/apps/converter/views.py b/mayan/apps/converter/views.py
index 02bfd4ad1f..19d7760081 100644
--- a/mayan/apps/converter/views.py
+++ b/mayan/apps/converter/views.py
@@ -55,7 +55,7 @@ class TransformationDeleteView(SingleObjectDeleteView):
 
 
 class TransformationCreateView(SingleObjectCreateView):
-    fields = ('name', 'arguments', 'order')
+    fields = ('name', 'arguments')
 
     def dispatch(self, request, *args, **kwargs):
         content_type = get_object_or_404(ContentType, app_label=self.kwargs['app_label'], model=self.kwargs['model'])