diff --git a/htdocs/main.inc.php b/htdocs/main.inc.php
index 7c682756edd..62f0271ebd0 100644
--- a/htdocs/main.inc.php
+++ b/htdocs/main.inc.php
@@ -164,7 +164,10 @@ if (! defined('NOSCANPOSTFORINJECTION'))
 }
 
 // This is to make Dolibarr working with Plesk
-if (! empty($_SERVER['DOCUMENT_ROOT'])) set_include_path($_SERVER['DOCUMENT_ROOT'].'/htdocs');
+if (! empty($_SERVER['DOCUMENT_ROOT']) && substr($_SERVER['DOCUMENT_ROOT'], -6) !== 'htdocs') {
+		set_include_path($_SERVER['DOCUMENT_ROOT'] . '/htdocs');
+	}
+}
 
 // Include the conf.php and functions.lib.php
 require_once 'filefunc.inc.php';