diff --git a/course/classes/local/service/content_item_service.php b/course/classes/local/service/content_item_service.php
index ca60efbc146..832a7eb63f8 100644
--- a/course/classes/local/service/content_item_service.php
+++ b/course/classes/local/service/content_item_service.php
@@ -110,7 +110,12 @@ class content_item_service {
             throw new \coding_exception('The guest user does not exist in the database.');
         }
 
-        $favourites = $this->get_content_favourites(self::RECOMMENDATION_PREFIX, \context_user::instance($CFG->siteguest));
+        // Make sure the guest user context exists.
+        if (!$guestusercontext = \context_user::instance($CFG->siteguest, false)) {
+            throw new \coding_exception('The guest user context does not exist.');
+        }
+
+        $favourites = $this->get_content_favourites(self::RECOMMENDATION_PREFIX, $guestusercontext);
 
         $recommendationcache->set($CFG->siteguest, $favourites);
         return $favourites;
diff --git a/lib/db/upgrade.php b/lib/db/upgrade.php
index 69527d99803..697d9de83bd 100644
--- a/lib/db/upgrade.php
+++ b/lib/db/upgrade.php
@@ -2815,5 +2815,41 @@ function xmldb_main_upgrade($oldversion) {
         upgrade_main_savepoint(true, 2021052500.27);
     }
 
+    if ($oldversion < 2021052500.29) {
+        // Get the current guest user which is also set as 'deleted'.
+        $guestuser = $DB->get_record('user', ['id' => $CFG->siteguest, 'deleted' => 1]);
+        // If there is a deleted guest user, reset the user to not be deleted and make sure the related
+        // user context exists.
+        if ($guestuser) {
+            $guestuser->deleted = 0;
+            $DB->update_record('user', $guestuser);
+
+            // Get the guest user context.
+            $guestusercontext = $DB->get_record('context',
+                ['contextlevel' => CONTEXT_USER, 'instanceid' => $guestuser->id]);
+
+            // If the guest user context does not exist, create it.
+            if (!$guestusercontext) {
+                $record = new stdClass();
+                $record->contextlevel = CONTEXT_USER;
+                $record->instanceid = $guestuser->id;
+                $record->depth = 0;
+                // The path is not known before insert.
+                $record->path = null;
+                $record->locked = 0;
+
+                $record->id = $DB->insert_record('context', $record);
+
+                // Update the path.
+                $record->path = '/' . SYSCONTEXTID . '/' . $record->id;
+                $record->depth = substr_count($record->path, '/');
+                $DB->update_record('context', $record);
+            }
+        }
+
+        // Main savepoint reached.
+        upgrade_main_savepoint(true, 2021052500.29);
+    }
+
     return true;
 }
diff --git a/version.php b/version.php
index b311bce33d9..13d25773a3b 100644
--- a/version.php
+++ b/version.php
@@ -29,7 +29,7 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$version  = 2021052500.28;              // YYYYMMDD      = weekly release date of this DEV branch.
+$version  = 2021052500.29;              // YYYYMMDD      = weekly release date of this DEV branch.
                                         //         RR    = release increments - 00 in DEV branches.
                                         //           .XX = incremental changes.
 $release  = '4.0dev (Build: 20201021)'; // Human-friendly version name