diff --git a/admin/include/functions.php b/admin/include/functions.php
index fac387eed..3d8ffa756 100644
--- a/admin/include/functions.php
+++ b/admin/include/functions.php
@@ -625,32 +625,6 @@ function get_fs_directories($path, $recursive = true)
   return $dirs;
 }
 
-/**
- * returns the size (in bytes) of a filesystem directory
- *
- * @since 11
- * @param string path
- * @return int
- */
-function get_fs_directory_size($path)
-{
-  $bytestotal = 0;
-  $path = realpath($path);
-
-  if (!function_exists('exec'))
-  {
-    return false;
-  }
-
-  @exec('du -sk '.$path, $returnarray);
-  if (is_array($returnarray) and !empty($returnarray[0]) and preg_match('/^(\d+)\s/', $returnarray[0], $matches))
-  {
-    $bytestotal = $matches[1] * 1024;
-  }
-
-  return $bytestotal;
-}
-
 /**
  * save the rank depending on given categories order
  *
diff --git a/admin/intro.php b/admin/intro.php
index ad14b8ccf..c3219a92c 100644
--- a/admin/intro.php
+++ b/admin/intro.php
@@ -409,24 +409,6 @@ if (isset($result[0]['SUM(filesize)']))
   $data_storage['Formats'] = $result[0]['SUM(filesize)'];
 }
 
-// Windows can't execute get_fs_directory_size correctly
-if (strtoupper(substr(PHP_OS, 0, 3)) !== 'WIN')
-{
-  if (!isset($_SESSION['cachedir_info']) or $_SESSION['cachedir_info']['calculated_on'] < strtotime('5 minutes ago'))
-  {
-    $start_time = get_moment();
-
-    $_SESSION['cachedir_info'] = array(
-      'size' => get_fs_directory_size($conf['data_location']),
-      'calculated_on' => time(),
-    );
-
-    $logger->debug('[admin/intro::'.__LINE__.'] cache size calculated in '.get_elapsed_time($start_time, get_moment()).' ('.$_SESSION['cachedir_info']['size'].' bytes)');
- }
-
-  $data_storage['Cache'] = $_SESSION['cachedir_info']['size'] / 1000;
-}
-
 //Calculate total storage
 $total_storage = 0;
 foreach ($data_storage as $value)