diff --git a/repository/filesystem/classes/task/cron_task.php b/repository/filesystem/classes/task/cron_task.php
new file mode 100644
index 00000000000..026a53c10c1
--- /dev/null
+++ b/repository/filesystem/classes/task/cron_task.php
@@ -0,0 +1,72 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace repository_filesystem\task;
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * A schedule task for file system repository cron.
+ *
+ * @package   repository_filesystem
+ * @copyright 2019 Simey Lameze <simey@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class cron_task extends \core\task\scheduled_task {
+    /**
+     * Get a descriptive name for this task (shown to admins).
+     *
+     * @return string
+     */
+    public function get_name() {
+        return get_string('crontask', 'repository_filesystem');
+    }
+
+    /**
+     * Run file system repository cron.
+     */
+    public function execute() {
+        global $CFG;
+        require_once($CFG->dirroot . '/repository/lib.php');
+        
+        $fs = get_file_storage();
+        // Find all generated thumbnails and group them in array by itemid (itemid == repository instance id).
+        $allfiles = array_merge(
+            $fs->get_area_files(SYSCONTEXTID, 'repository_filesystem', 'thumb'),
+            $fs->get_area_files(SYSCONTEXTID, 'repository_filesystem', 'icon')
+        );
+        $filesbyitem = array();
+        foreach ($allfiles as $file) {
+            if (!isset($filesbyitem[$file->get_itemid()])) {
+                $filesbyitem[$file->get_itemid()] = array();
+            }
+            $filesbyitem[$file->get_itemid()][] = $file;
+        }
+        // Find all instances of repository_filesystem.
+        $instances = \repository::get_instances(array('type' => 'filesystem'));
+        // Loop through all itemids of generated thumbnails.
+        foreach ($filesbyitem as $itemid => $files) {
+            if (!isset($instances[$itemid]) || !($instances[$itemid] instanceof repository_filesystem)) {
+                // Instance was deleted.
+                $fs->delete_area_files(SYSCONTEXTID, 'repository_filesystem', 'thumb', $itemid);
+                $fs->delete_area_files(SYSCONTEXTID, 'repository_filesystem', 'icon', $itemid);
+                mtrace(" instance $itemid does not exist: deleted all thumbnails");
+            } else {
+                // Instance has some generated thumbnails, check that they are not outdated.
+                $instances[$itemid]->remove_obsolete_thumbnails($files);
+            }
+        }
+    }
+}
diff --git a/repository/filesystem/db/tasks.php b/repository/filesystem/db/tasks.php
new file mode 100644
index 00000000000..5f0cd109498
--- /dev/null
+++ b/repository/filesystem/db/tasks.php
@@ -0,0 +1,34 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+/**
+ * Definition of file system repository scheduled tasks.
+ *
+ * @package   repository_filesystem
+ * @copyright 2019 Simey Lameze <simey@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+defined('MOODLE_INTERNAL') || die();
+$tasks = array(
+    array(
+        'classname' => '\repository_filesystem\task\cron_task',
+        'blocking' => 0,
+        'minute' => '*',
+        'hour' => '*',
+        'day' => '*',
+        'month' => '*',
+        'dayofweek' => '*'
+    )
+);
diff --git a/repository/filesystem/lang/en/repository_filesystem.php b/repository/filesystem/lang/en/repository_filesystem.php
index c292f23a0e1..4b4650f1786 100644
--- a/repository/filesystem/lang/en/repository_filesystem.php
+++ b/repository/filesystem/lang/en/repository_filesystem.php
@@ -25,6 +25,7 @@
 
 $string['blockedpath'] = 'Blocked root path';
 $string['configplugin'] = 'Configuration for file system repository';
+$string['crontask'] = 'Background processing for filesystem repository';
 $string['donotusesysdir'] = 'Don\'t use system directory as repository, including';
 $string['filesystem:view'] = 'View file system repository';
 $string['information'] = 'These folders are within the <b>{$a}</b> directory.';
diff --git a/repository/filesystem/version.php b/repository/filesystem/version.php
index c4d65fbebc4..490c07b2a8e 100644
--- a/repository/filesystem/version.php
+++ b/repository/filesystem/version.php
@@ -26,6 +26,6 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$plugin->version   = 2018120300;        // The current plugin version (Date: YYYYMMDDXX)
+$plugin->version   = 2018120301;        // The current plugin version (Date: YYYYMMDDXX)
 $plugin->requires  = 2018112800;        // Requires this Moodle version
 $plugin->component = 'repository_filesystem'; // Full name of the plugin (used for diagnostics)