diff --git a/htdocs/resource/class/dolresource.class.php b/htdocs/resource/class/dolresource.class.php
index ec184cd856d..ba962bf48c1 100644
--- a/htdocs/resource/class/dolresource.class.php
+++ b/htdocs/resource/class/dolresource.class.php
@@ -408,6 +408,7 @@ class Dolresource extends CommonObject
 	function delete($rowid, $notrigger=0)
 	{
 		global $user,$langs,$conf;
+        require_once DOL_DOCUMENT_ROOT . '/core/lib/files.lib.php';
 
 		$error=0;