diff --git a/admin/tool/monitor/classes/eventobservers.php b/admin/tool/monitor/classes/eventobservers.php
index 793b11f315b..bc9a0fae3e0 100644
--- a/admin/tool/monitor/classes/eventobservers.php
+++ b/admin/tool/monitor/classes/eventobservers.php
@@ -53,10 +53,13 @@ class eventobservers {
      * @param \core\event\course_deleted $event The course deleted event.
      */
     public static function course_deleted(\core\event\course_deleted $event) {
+        // Delete rules defined inside this course and associated subscriptions.
         $rules = rule_manager::get_rules_by_courseid($event->courseid, 0, 0, false);
         foreach ($rules as $rule) {
             rule_manager::delete_rule($rule->id, $event->get_context());
         }
+        // Delete remaining subscriptions inside this course (from site-wide rules).
+        subscription_manager::remove_all_subscriptions_in_course($event->get_context());
     }
 
     /**
diff --git a/admin/tool/monitor/classes/subscription.php b/admin/tool/monitor/classes/subscription.php
index 98518e9a4df..e057441850b 100644
--- a/admin/tool/monitor/classes/subscription.php
+++ b/admin/tool/monitor/classes/subscription.php
@@ -176,8 +176,12 @@ class subscription {
         if (empty($courseid)) {
             return get_string('site');
         } else {
-            $course = get_course($courseid);
-            return format_string($course->fullname, true, array('context' => $context));
+            try {
+                $course = get_course($courseid);
+                return format_string($course->fullname, true, array('context' => $context));
+            } catch (\dml_exception $e) {
+                return '-';
+            }
         }
     }
 
diff --git a/admin/tool/monitor/classes/subscription_manager.php b/admin/tool/monitor/classes/subscription_manager.php
index 33ba9c3cad5..ff8ba16fb80 100644
--- a/admin/tool/monitor/classes/subscription_manager.php
+++ b/admin/tool/monitor/classes/subscription_manager.php
@@ -118,9 +118,10 @@ class subscription_manager {
 
         // If successful trigger a subscription_deleted event.
         if ($success) {
-            if (!empty($subscription->courseid)) {
+            if (!empty($subscription->courseid) &&
+                    ($coursecontext = \context_course::instance($subscription->courseid, IGNORE_MISSING))) {
                 $courseid = $subscription->courseid;
-                $context = \context_course::instance($subscription->courseid);
+                $context = $coursecontext;
             } else {
                 $courseid = 0;
                 $context = \context_system::instance();
@@ -222,6 +223,31 @@ class subscription_manager {
         return $success;
     }
 
+    /**
+     * Delete all subscriptions in a course.
+     *
+     * This is called after a course was deleted, context no longer exists but we kept the object
+     *
+     * @param \context_course $coursecontext the context of the course
+     */
+    public static function remove_all_subscriptions_in_course($coursecontext) {
+        global $DB;
+
+        // Store all the subscriptions we have to delete.
+        if ($subscriptions = $DB->get_records('tool_monitor_subscriptions', array('courseid' => $coursecontext->instanceid))) {
+            // Delete subscriptions in bulk.
+            $DB->delete_records('tool_monitor_subscriptions', array('courseid' => $coursecontext->instanceid));
+
+            // Trigger events one by one.
+            foreach ($subscriptions as $subscription) {
+                $params = ['objectid' => $subscription->id, 'context' => $coursecontext];
+                $event = \tool_monitor\event\subscription_deleted::create($params);
+                $event->add_record_snapshot('tool_monitor_subscriptions', $subscription);
+                $event->trigger();
+            }
+        }
+    }
+
     /**
      * Get a subscription instance for an given subscription id.
      *
diff --git a/admin/tool/monitor/db/upgrade.php b/admin/tool/monitor/db/upgrade.php
index aaea29a1503..55a7446f10c 100644
--- a/admin/tool/monitor/db/upgrade.php
+++ b/admin/tool/monitor/db/upgrade.php
@@ -77,5 +77,21 @@ function xmldb_tool_monitor_upgrade($oldversion) {
         upgrade_plugin_savepoint(true, 2016052305, 'tool', 'monitor');
     }
 
+    if ($oldversion < 2016052306) {
+
+        // Delete "orphaned" subscriptions.
+        $deletedcourses = $DB->get_field_sql("SELECT DISTINCT s.courseid
+            FROM {tool_monitor_subscriptions} s
+            LEFT OUTER JOIN {course} c ON c.id = s.courseid
+            WHERE s.courseid <> 0 and c.id IS NULL");
+        if ($deletedcourses) {
+            list($sql, $params) = $DB->get_in_or_equal($deletedcourses);
+            $DB->execute("DELETE FROM {tool_monitor_subscriptions} WHERE courseid " . $sql, $params);
+        }
+
+        // Monitor savepoint reached.
+        upgrade_plugin_savepoint(true, 2016052306, 'tool', 'monitor');
+    }
+
     return true;
 }
diff --git a/admin/tool/monitor/version.php b/admin/tool/monitor/version.php
index 9e5a5a394ba..925d18f8061 100644
--- a/admin/tool/monitor/version.php
+++ b/admin/tool/monitor/version.php
@@ -26,6 +26,6 @@
 
 defined('MOODLE_INTERNAL') || die;
 
-$plugin->version   = 2016052305;     // The current plugin version (Date: YYYYMMDDXX).
+$plugin->version   = 2016052306;     // The current plugin version (Date: YYYYMMDDXX).
 $plugin->requires  = 2016051900;     // Requires this Moodle version.
 $plugin->component = 'tool_monitor'; // Full name of the plugin (used for diagnostics).