diff --git a/admin/tool/uploadcourse/classes/step2_form.php b/admin/tool/uploadcourse/classes/step2_form.php
index a6875f68263..4cd4f27c2be 100644
--- a/admin/tool/uploadcourse/classes/step2_form.php
+++ b/admin/tool/uploadcourse/classes/step2_form.php
@@ -84,6 +84,7 @@ class tool_uploadcourse_step2_form extends tool_uploadcourse_base_form {
 
         $displaylist = core_course_category::make_categories_list('moodle/course:create');
         $mform->addElement('autocomplete', 'defaults[category]', get_string('coursecategory'), $displaylist);
+        $mform->addRule('defaults[category]', null, 'required', null, 'client');
         $mform->addHelpButton('defaults[category]', 'coursecategory');
 
         $choices = array();
diff --git a/backup/util/ui/classes/output/copy_form.php b/backup/util/ui/classes/output/copy_form.php
index 51f8bb8815f..78d56c796c7 100644
--- a/backup/util/ui/classes/output/copy_form.php
+++ b/backup/util/ui/classes/output/copy_form.php
@@ -107,6 +107,7 @@ class copy_form extends \moodleform {
             $displaylist[$course->category] = \core_course_category::get($course->category, MUST_EXIST, true)->get_formatted_name();
         }
         $mform->addElement('autocomplete', 'category', get_string('coursecategory'), $displaylist);
+        $mform->addRule('category', null, 'required', null, 'client');
         $mform->addHelpButton('category', 'coursecategory');
 
         // Course visibility.
diff --git a/cohort/edit_form.php b/cohort/edit_form.php
index 77599fd1dc2..55e7a54284d 100644
--- a/cohort/edit_form.php
+++ b/cohort/edit_form.php
@@ -44,6 +44,7 @@ class cohort_edit_form extends moodleform {
 
         $options = $this->get_category_options($cohort->contextid);
         $mform->addElement('autocomplete', 'contextid', get_string('context', 'role'), $options);
+        $mform->addRule('contextid', null, 'required', null, 'client');
 
         $mform->addElement('text', 'idnumber', get_string('idnumber', 'cohort'), 'maxlength="254" size="50"');
         $mform->setType('idnumber', PARAM_RAW); // Idnumbers are plain text, must not be changed.
diff --git a/course/classes/deletecategory_form.php b/course/classes/deletecategory_form.php
index 906837e505d..a56661148e9 100644
--- a/course/classes/deletecategory_form.php
+++ b/course/classes/deletecategory_form.php
@@ -112,6 +112,7 @@ class core_course_deletecategory_form extends moodleform {
 
         if ($displaylist) {
             $mform->addElement('autocomplete', 'newparent', get_string('movecategorycontentto'), $displaylist);
+            $mform->addRule('newparent', null, 'required', null, 'client');
             if (in_array($this->coursecat->parent, $displaylist)) {
                 $mform->setDefault('newparent', $this->coursecat->parent);
             }
diff --git a/course/classes/editcategory_form.php b/course/classes/editcategory_form.php
index 236fbad0901..1006fb4e572 100644
--- a/course/classes/editcategory_form.php
+++ b/course/classes/editcategory_form.php
@@ -64,6 +64,7 @@ class core_course_editcategory_form extends moodleform {
         }
 
         $mform->addElement('autocomplete', 'parent', get_string('parentcategory'), $options);
+        $mform->addRule('parent', null, 'required', null, 'client');
 
         $mform->addElement('text', 'name', get_string('categoryname'), array('size' => '30'));
         $mform->addRule('name', get_string('required'), 'required', null);
diff --git a/course/edit_form.php b/course/edit_form.php
index 73b5190c3bf..5654393df0a 100644
--- a/course/edit_form.php
+++ b/course/edit_form.php
@@ -78,6 +78,7 @@ class course_edit_form extends moodleform {
             if (has_capability('moodle/course:create', $categorycontext)) {
                 $displaylist = core_course_category::make_categories_list('moodle/course:create');
                 $mform->addElement('autocomplete', 'category', get_string('coursecategory'), $displaylist);
+                $mform->addRule('category', null, 'required', null, 'client');
                 $mform->addHelpButton('category', 'coursecategory');
                 $mform->setDefault('category', $category->id);
             } else {
@@ -94,6 +95,7 @@ class course_edit_form extends moodleform {
                         ->get_formatted_name();
                 }
                 $mform->addElement('autocomplete', 'category', get_string('coursecategory'), $displaylist);
+                $mform->addRule('category', null, 'required', null, 'client');
                 $mform->addHelpButton('category', 'coursecategory');
             } else {
                 //keep current
diff --git a/course/request_form.php b/course/request_form.php
index d9179700119..332da47852d 100644
--- a/course/request_form.php
+++ b/course/request_form.php
@@ -71,6 +71,7 @@ class course_request_form extends moodleform {
         if (empty($CFG->lockrequestcategory)) {
             $displaylist = core_course_category::make_categories_list('moodle/course:request');
             $mform->addElement('autocomplete', 'category', get_string('coursecategory'), $displaylist);
+            $mform->addRule('category', null, 'required', null, 'client');
             $mform->setDefault('category', $CFG->defaultrequestcategory);
             $mform->addHelpButton('category', 'coursecategory');
         }