diff --git a/course/format/renderer.php b/course/format/renderer.php
index 74baa080b44..26f28c213b2 100644
--- a/course/format/renderer.php
+++ b/course/format/renderer.php
@@ -271,7 +271,7 @@ abstract class format_section_renderer_base extends plugin_renderer_base {
      *
      * @param stdClass $section The course_section entry from DB
      * @param stdClass $course The course entry from DB
-     * @param array    $mods course modules indexed by id (from get_fast_modinfo()->get_cms())
+     * @param array    $mods (argument not used)
      * @return string HTML to output.
      */
     protected function section_summary($section, $course, $mods) {
@@ -303,7 +303,7 @@ abstract class format_section_renderer_base extends plugin_renderer_base {
         $o.= html_writer::start_tag('div', array('class' => 'summarytext'));
         $o.= $this->format_summary_text($section);
         $o.= html_writer::end_tag('div');
-        $o.= $this->section_activity_summary($section, $course, $mods);
+        $o.= $this->section_activity_summary($section, $course, null);
 
         $o.= $this->section_availability_message($section);
 
@@ -318,11 +318,12 @@ abstract class format_section_renderer_base extends plugin_renderer_base {
      *
      * @param stdClass $section The course_section entry from DB
      * @param stdClass $course the course record from DB
-     * @param array    $mods course modules indexed by id (from get_fast_modinfo()->get_cms())
+     * @param array    $mods (argument not used)
      * @return string HTML to output.
      */
     private function section_activity_summary($section, $course, $mods) {
-        if (empty($section->sequence)) {
+        $modinfo = get_fast_modinfo($course);
+        if (empty($modinfo->sections[$section->section])) {
             return '';
         }
 
@@ -332,9 +333,8 @@ abstract class format_section_renderer_base extends plugin_renderer_base {
         $complete = 0;
         $cancomplete = isloggedin() && !isguestuser();
         $completioninfo = new completion_info($course);
-        $modsequence = explode(',', $section->sequence);
-        foreach ($modsequence as $cmid) {
-            $thismod = $mods[$cmid];
+        foreach ($modinfo->sections[$section->section] as $cmid) {
+            $thismod = $modinfo->cms[$cmid];
 
             if ($thismod->modname == 'label') {
                 // Labels are special (not interesting for students)!
@@ -343,9 +343,10 @@ abstract class format_section_renderer_base extends plugin_renderer_base {
 
             if ($thismod->uservisible) {
                 if (isset($sectionmods[$thismod->modname])) {
+                    $sectionmods[$thismod->modname]['name'] = $thismod->modplural;
                     $sectionmods[$thismod->modname]['count']++;
                 } else {
-                    $sectionmods[$thismod->modname]['name'] = $thismod->modplural;
+                    $sectionmods[$thismod->modname]['name'] = $thismod->modfullname;
                     $sectionmods[$thismod->modname]['count'] = 1;
                 }
                 if ($cancomplete && $completioninfo->is_enabled($thismod) != COMPLETION_TRACKING_NONE) {
@@ -531,26 +532,25 @@ abstract class format_section_renderer_base extends plugin_renderer_base {
      * Output the html for a single section page .
      *
      * @param stdClass $course The course entry from DB
-     * @param array $sections The course_sections entries from the DB
-     * @param array $mods used for print_section()
-     * @param array $modnames used for print_section()
-     * @param array $modnamesused used for print_section()
+     * @param array $sections (argument not used)
+     * @param array $mods (argument not used)
+     * @param array $modnames (argument not used)
+     * @param array $modnamesused (argument not used)
      * @param int $displaysection The section number in the course which is being displayed
      */
     public function print_single_section_page($course, $sections, $mods, $modnames, $modnamesused, $displaysection) {
         global $PAGE;
 
-        // Can we view the section in question?
-        $context = context_course::instance($course->id);
-        $canviewhidden = has_capability('moodle/course:viewhiddensections', $context);
+        $modinfo = get_fast_modinfo($course);
 
-        if (!isset($sections[$displaysection])) {
+        // Can we view the section in question?
+        if (!($sectioninfo = $modinfo->get_section_info($displaysection))) {
             // This section doesn't exist
             print_error('unknowncoursesection', 'error', null, $course->fullname);
             return;
         }
 
-        if (!$sections[$displaysection]->visible && !$canviewhidden) {
+        if (!$sectioninfo->uservisible) {
             if (!$course->hiddensections) {
                 echo $this->start_section_list();
                 echo $this->section_hidden($displaysection);
@@ -562,15 +562,13 @@ abstract class format_section_renderer_base extends plugin_renderer_base {
 
         // Copy activity clipboard..
         echo $this->course_activity_clipboard($course, $displaysection);
-
-        // General section if non-empty.
-        $thissection = $sections[0];
-        if ($thissection->summary or $thissection->sequence or $PAGE->user_is_editing()) {
+        $thissection = $modinfo->get_section_info(0);
+        if ($thissection->summary or !empty($modinfo->sections[0]) or $PAGE->user_is_editing()) {
             echo $this->start_section_list();
             echo $this->section_header($thissection, $course, true, $displaysection);
-            print_section($course, $thissection, $mods, $modnamesused, true, "100%", false, $displaysection);
+            print_section($course, $thissection, null, null, true, "100%", false, $displaysection);
             if ($PAGE->user_is_editing()) {
-                print_section_add_menus($course, 0, $modnames, false, false, $displaysection);
+                print_section_add_menus($course, 0, null, false, false, $displaysection);
             }
             echo $this->section_footer();
             echo $this->end_section_list();
@@ -579,34 +577,35 @@ abstract class format_section_renderer_base extends plugin_renderer_base {
         // Start single-section div
         echo html_writer::start_tag('div', array('class' => 'single-section'));
 
+        // The requested section page.
+        $thissection = $modinfo->get_section_info($displaysection);
+
         // Title with section navigation links.
-        $sectionnavlinks = $this->get_nav_links($course, $sections, $displaysection);
+        $sectionnavlinks = $this->get_nav_links($course, $modinfo->get_section_info_all(), $displaysection);
         $sectiontitle = '';
         $sectiontitle .= html_writer::start_tag('div', array('class' => 'section-navigation header headingblock'));
         $sectiontitle .= html_writer::tag('span', $sectionnavlinks['previous'], array('class' => 'mdl-left'));
         $sectiontitle .= html_writer::tag('span', $sectionnavlinks['next'], array('class' => 'mdl-right'));
         // Title attributes
         $titleattr = 'mdl-align title';
-        if (!$sections[$displaysection]->visible) {
+        if (!$thissection->visible) {
             $titleattr .= ' dimmed_text';
         }
-        $sectiontitle .= html_writer::tag('div', get_section_name($course, $sections[$displaysection]), array('class' => $titleattr));
+        $sectiontitle .= html_writer::tag('div', get_section_name($course, $displaysection), array('class' => $titleattr));
         $sectiontitle .= html_writer::end_tag('div');
         echo $sectiontitle;
 
         // Now the list of sections..
         echo $this->start_section_list();
 
-        // The requested section page.
-        $thissection = $sections[$displaysection];
         echo $this->section_header($thissection, $course, true, $displaysection);
         // Show completion help icon.
         $completioninfo = new completion_info($course);
         echo $completioninfo->display_help_icon();
 
-        print_section($course, $thissection, $mods, $modnamesused, true, '100%', false, $displaysection);
+        print_section($course, $thissection, null, null, true, '100%', false, $displaysection);
         if ($PAGE->user_is_editing()) {
-            print_section_add_menus($course, $displaysection, $modnames, false, false, $displaysection);
+            print_section_add_menus($course, $displaysection, null, false, false, $displaysection);
         }
         echo $this->section_footer();
         echo $this->end_section_list();
@@ -629,14 +628,16 @@ abstract class format_section_renderer_base extends plugin_renderer_base {
      * Output the html for a multiple section page
      *
      * @param stdClass $course The course entry from DB
-     * @param array $sections The course_sections entries from the DB
-     * @param array $mods used for print_section()
-     * @param array $modnames used for print_section()
-     * @param array $modnamesused used for print_section()
+     * @param array $sections (argument not used)
+     * @param array $mods (argument not used)
+     * @param array $modnames (argument not used)
+     * @param array $modnamesused (argument not used)
      */
     public function print_multiple_section_page($course, $sections, $mods, $modnames, $modnamesused) {
         global $PAGE;
 
+        $modinfo = get_fast_modinfo($course);
+
         $context = context_course::instance($course->id);
         // Title with completion help icon.
         $completioninfo = new completion_info($course);
@@ -649,32 +650,22 @@ abstract class format_section_renderer_base extends plugin_renderer_base {
         // Now the list of sections..
         echo $this->start_section_list();
 
-        // General section if non-empty.
-        $thissection = $sections[0];
-        unset($sections[0]);
-        if ($thissection->summary or $thissection->sequence or $PAGE->user_is_editing()) {
-            echo $this->section_header($thissection, $course, false, 0);
-            print_section($course, $thissection, $mods, $modnamesused, true, "100%", false, 0);
-            if ($PAGE->user_is_editing()) {
-                print_section_add_menus($course, 0, $modnames, false, false, 0);
+        foreach ($modinfo->get_section_info_all() as $section => $thissection) {
+            if ($section == 0) {
+                // 0-section is displayed a little different then the others
+                if ($thissection->summary or !empty($modinfo->sections[0]) or $PAGE->user_is_editing()) {
+                    echo $this->section_header($thissection, $course, false, 0);
+                    print_section($course, $thissection, null, null, true, "100%", false, 0);
+                    if ($PAGE->user_is_editing()) {
+                        print_section_add_menus($course, 0, null, false, false, 0);
+                    }
+                    echo $this->section_footer();
+                }
+                continue;
             }
-            echo $this->section_footer();
-        }
-
-        $canviewhidden = has_capability('moodle/course:viewhiddensections', $context);
-        for ($section = 1; $section <= $course->numsections; $section++) {
-            if (!empty($sections[$section])) {
-                $thissection = $sections[$section];
-            } else {
-                // This will create a course section if it doesn't exist..
-                $thissection = get_course_section($section, $course->id);
-
-                // The returned section is only a bare database object rather than
-                // a section_info object - we will need at least the uservisible
-                // field in it.
-                $thissection->uservisible = true;
-                $thissection->availableinfo = null;
-                $thissection->showavailability = 0;
+            if ($section > $course->numsections) {
+                // activities inside this section are 'orphaned', this section will be printed as 'stealth' below
+                continue;
             }
             // Show the section if the user is permitted to access it, OR if it's not available
             // but showavailability is turned on
@@ -687,36 +678,33 @@ abstract class format_section_renderer_base extends plugin_renderer_base {
                     echo $this->section_hidden($section);
                 }
 
-                unset($sections[$section]);
                 continue;
             }
 
             if (!$PAGE->user_is_editing() && $course->coursedisplay == COURSE_DISPLAY_MULTIPAGE) {
                 // Display section summary only.
-                echo $this->section_summary($thissection, $course, $mods);
+                echo $this->section_summary($thissection, $course, null);
             } else {
                 echo $this->section_header($thissection, $course, false, 0);
                 if ($thissection->uservisible) {
-                    print_section($course, $thissection, $mods, $modnamesused, true, "100%", false, 0);
+                    print_section($course, $thissection, null, null, true, "100%", false, 0);
                     if ($PAGE->user_is_editing()) {
-                        print_section_add_menus($course, $section, $modnames, false, false, 0);
+                        print_section_add_menus($course, $section, null, false, false, 0);
                     }
                 }
                 echo $this->section_footer();
             }
-
-            unset($sections[$section]);
         }
 
         if ($PAGE->user_is_editing() and has_capability('moodle/course:update', $context)) {
             // Print stealth sections if present.
-            $modinfo = get_fast_modinfo($course);
-            foreach ($sections as $section => $thissection) {
-                if (empty($modinfo->sections[$section])) {
+            foreach ($modinfo->get_section_info_all() as $section => $thissection) {
+                if ($section <= $course->numsections or empty($modinfo->sections[$section])) {
+                    // this is not stealth section or it is empty
                     continue;
                 }
                 echo $this->stealth_section_header($section);
-                print_section($course, $thissection, $mods, $modnamesused, true, "100%", false, $displaysection);
+                print_section($course, $thissection, null, null, true, "100%", false, 0);
                 echo $this->stealth_section_footer();
             }
 
diff --git a/course/format/topics/format.php b/course/format/topics/format.php
index 51acd387461..e69ac91d532 100644
--- a/course/format/topics/format.php
+++ b/course/format/topics/format.php
@@ -44,12 +44,20 @@ if (($marker >=0) && has_capability('moodle/course:setcurrentsection', $context)
     course_set_marker($course->id, $marker);
 }
 
+// make sure all sections are created
+$modinfo = get_fast_modinfo($course);
+for ($sectionnum = 0; $sectionnum <= $course->numsections; $sectionnum++) {
+    if (!$modinfo->get_section_info($sectionnum)) {
+        get_course_section($sectionnum, $course->id);
+    }
+}
+
 $renderer = $PAGE->get_renderer('format_topics');
 
 if (!empty($displaysection)) {
-    $renderer->print_single_section_page($course, $sections, $mods, $modnames, $modnamesused, $displaysection);
+    $renderer->print_single_section_page($course, null, null, null, null, $displaysection);
 } else {
-    $renderer->print_multiple_section_page($course, $sections, $mods, $modnames, $modnamesused);
+    $renderer->print_multiple_section_page($course, null, null, null, null);
 }
 
 // Include course format js module
diff --git a/course/format/weeks/format.php b/course/format/weeks/format.php
index 2f0eb51f4d9..b35a327e790 100644
--- a/course/format/weeks/format.php
+++ b/course/format/weeks/format.php
@@ -37,12 +37,20 @@ if ($week = optional_param('week', 0, PARAM_INT)) {
 }
 // End backwards-compatible aliasing..
 
+// make sure all sections are created
+$modinfo = get_fast_modinfo($course);
+for ($sectionnum = 0; $sectionnum <= $course->numsections; $sectionnum++) {
+    if (!$modinfo->get_section_info($sectionnum)) {
+        get_course_section($sectionnum, $course->id);
+    }
+}
+
 $renderer = $PAGE->get_renderer('format_weeks');
 
 if (!empty($displaysection)) {
-    $renderer->print_single_section_page($course, $sections, $mods, $modnames, $modnamesused, $displaysection);
+    $renderer->print_single_section_page($course, null, null, null, null, $displaysection);
 } else {
-    $renderer->print_multiple_section_page($course, $sections, $mods, $modnames, $modnamesused);
+    $renderer->print_multiple_section_page($course, null, null, null, null);
 }
 
 $PAGE->requires->js('/course/format/weeks/format.js');
diff --git a/course/lib.php b/course/lib.php
index 1a246a20ab4..3f3cbe5b9f6 100644
--- a/course/lib.php
+++ b/course/lib.php
@@ -1332,9 +1332,9 @@ function get_print_section_cm_text(cm_info $cm, $course) {
  * Prints a section full of activity modules
  *
  * @param stdClass $course The course
- * @param stdClass $section The section
- * @param array $mods The modules in the section
- * @param array $modnamesused An array containing the list of modules and their names
+ * @param stdClass|section_info $section The section object containing properties id and section
+ * @param array $mods (argument not used)
+ * @param array $modnamesused (argument not used)
  * @param bool $absolute All links are absolute
  * @param string $width Width of the container
  * @param bool $hidecompletion Hide completion status
@@ -1353,7 +1353,6 @@ function print_section($course, $section, $mods, $modnamesused, $absolute=false,
     static $strmovehere;
     static $strmovefull;
     static $strunreadpostsone;
-    static $modulenames;
 
     if (!isset($initialised)) {
         $groupbuttons     = ($course->groupmode or (!$course->groupmodeforce));
@@ -1364,7 +1363,6 @@ function print_section($course, $section, $mods, $modnamesused, $absolute=false,
             $strmovehere  = get_string("movehere");
             $strmovefull  = strip_tags(get_string("movefull", "", "'$USER->activitycopyname'"));
         }
-        $modulenames      = array();
         $initialised = true;
     }
 
@@ -1372,62 +1370,37 @@ function print_section($course, $section, $mods, $modnamesused, $absolute=false,
     $completioninfo = new completion_info($course);
 
     //Accessibility: replace table with list <ul>, but don't output empty list.
-    if (!empty($section->sequence)) {
+    if (!empty($modinfo->sections[$section->section])) {
 
         // Fix bug #5027, don't want style=\"width:$width\".
         echo "<ul class=\"section img-text\">\n";
-        $sectionmods = explode(",", $section->sequence);
 
-        foreach ($sectionmods as $modnumber) {
-            if (empty($mods[$modnumber])) {
-                continue;
-            }
-
-            /**
-             * @var cm_info
-             */
-            $mod = $mods[$modnumber];
+        foreach ($modinfo->sections[$section->section] as $modnumber) {
+            $mod = $modinfo->cms[$modnumber];
 
             if ($ismoving and $mod->id == $USER->activitycopy) {
                 // do not display moving mod
                 continue;
             }
 
-            if (isset($modinfo->cms[$modnumber])) {
-                // We can continue (because it will not be displayed at all)
-                // if:
-                // 1) The activity is not visible to users
-                // and
-                // 2a) The 'showavailability' option is not set (if that is set,
-                //     we need to display the activity so we can show
-                //     availability info)
-                // or
-                // 2b) The 'availableinfo' is empty, i.e. the activity was
-                //     hidden in a way that leaves no info, such as using the
-                //     eye icon.
-                if (!$modinfo->cms[$modnumber]->uservisible &&
-                    (empty($modinfo->cms[$modnumber]->showavailability) ||
-                      empty($modinfo->cms[$modnumber]->availableinfo))) {
-                    // visibility shortcut
-                    continue;
-                }
-            } else {
-                if (!file_exists("$CFG->dirroot/mod/$mod->modname/lib.php")) {
-                    // module not installed
-                    continue;
-                }
-                if (!coursemodule_visible_for_user($mod) &&
-                    empty($mod->showavailability)) {
-                    // full visibility check
-                    continue;
-                }
+            // We can continue (because it will not be displayed at all)
+            // if:
+            // 1) The activity is not visible to users
+            // and
+            // 2a) The 'showavailability' option is not set (if that is set,
+            //     we need to display the activity so we can show
+            //     availability info)
+            // or
+            // 2b) The 'availableinfo' is empty, i.e. the activity was
+            //     hidden in a way that leaves no info, such as using the
+            //     eye icon.
+            if (!$mod->uservisible &&
+                (empty($mod->showavailability) ||
+                  empty($mod->availableinfo))) {
+                // visibility shortcut
+                continue;
             }
 
-            if (!isset($modulenames[$mod->modname])) {
-                $modulenames[$mod->modname] = get_string('modulename', $mod->modname);
-            }
-            $modulename = $modulenames[$mod->modname];
-
             // In some cases the activity is visible to user, but it is
             // dimmed. This is done if viewhiddenactivities is true and if:
             // 1. the activity is not visible, or
@@ -1710,7 +1683,7 @@ function print_section($course, $section, $mods, $modnamesused, $absolute=false,
              ' alt="'.$strmovehere.'" /></a></li>
              ';
     }
-    if (!empty($section->sequence) || $ismoving) {
+    if (!empty($modinfo->sections[$section->section]) || $ismoving) {
         echo "</ul><!--class='section'-->\n\n";
     }
 }