diff --git a/date_popup/date_popup.module b/date_popup/date_popup.module
index a03132e..f589cf2 100644
--- a/date_popup/date_popup.module
+++ b/date_popup/date_popup.module
@@ -543,6 +543,10 @@ function date_popup_process_time_part(&$element) {
  * contains a string, after submission it contains an array.
  */
 function date_popup_validate($element, &$form_state) {
+  if (!empty($element['#disabled'])) {
+    // There is no useful state and the result is ignored anyway.
+    return;
+  }
 
   if (date_hidden_element($element)) {
     return;