diff --git a/date_api/date_api_ical.inc b/date_api/date_api_ical.inc
index 2ca484e..ef3a19f 100644
--- a/date_api/date_api_ical.inc
+++ b/date_api/date_api_ical.inc
@@ -722,6 +722,9 @@ function date_api_ical_build_rrule($form_values) {
   if (array_key_exists('BYMONTHDAY', $form_values) && is_array($form_values['BYMONTHDAY']) && $BYMONTHDAY = implode(",", $form_values['BYMONTHDAY'])) {
     $RRULE .= ';BYMONTHDAY=' . $BYMONTHDAY;
   }
+  
+  // We can only set UNTIL OR COUNT. We cannot set both per RFC-2445.
+  
   // The UNTIL date is supposed to always be expressed in UTC.
   // The input date values may already have been converted to a date object on a
   // previous pass, so check for that.
@@ -741,10 +744,10 @@ function date_api_ical_build_rrule($form_values) {
       $until = $form_values['UNTIL']['datetime'];
     }
     $RRULE .= ';UNTIL=' . date_format($until, DATE_FORMAT_ICAL) . 'Z';
-  }
+  } else if (array_key_exists('COUNT', $form_values) && is_int($form_values['COUNT'])) {
   // Our form doesn't allow a value for COUNT, but it may be needed by
   // modules using the API, so add it to the rule.
-  if (array_key_exists('COUNT', $form_values)) {
+  // COUNT is not allowed to be empty per RFC-2445.
     $RRULE .= ';COUNT=' . $form_values['COUNT'];
   }