diff -u b/core/includes/form.inc b/core/includes/form.inc
--- b/core/includes/form.inc
+++ b/core/includes/form.inc
@@ -2907,7 +2907,7 @@
       form_error($element, t('The specified passwords do not match.'));
     }
   }
-  elseif (!empty($element['#required_but_empty'])) {
+  elseif (!empty($element['#required_but_empty']) || ($element['#required'] && !empty($element_state['input']))) {
     form_error($element, t('Password field is required.'));
   }
 
@@ -3288,7 +3288,7 @@
  * @see form_process_pattern()
  */
 function form_validate_pattern($element, &$form_state) {
-  if (empty($element['#required_but_empty']) && $element['#value'] !== '') {
+  if (!empty($element['#required_but_empty']) || $element['#value'] !== '') {
     // The pattern must match the entire string and should have the same
     // behavior as the RegExp object in ECMA 262.
     // - Use bracket-style delimiters to avoid introducing a special delimiter
@@ -4115,7 +4115,7 @@
  */
 function form_validate_number(&$element, &$form_state) {
   $value = $element['#value'];
-  if (empty($element['#required_but_empty']) || $value === '') {
+  if (!empty($element['#required_but_empty']) || $value === '') {
     return;
   }