diff --git a/htdocs/index.php b/htdocs/index.php
index 6b5b6883c5c..9e28d265220 100644
--- a/htdocs/index.php
+++ b/htdocs/index.php
@@ -58,7 +58,7 @@ if (defined("MAIN_MOTD") && strlen(trim(MAIN_MOTD)))
 // Affiche warning répertoire install existe (si utilisateur admin)
 if ($user->admin && ! defined("MAIN_REMOVE_INSTALL_WARNING"))
 {
-	if (is_dir(DOL_DOCUMENT_ROOT."/install") && is_executable(DOL_DOCUMENT_ROOT."/install"))
+	if (is_dir(DOL_DOCUMENT_ROOT."/install") && (function_exists('is_executable') && @is_executable(DOL_DOCUMENT_ROOT."/install")))
   {
   	$langs->load("other");
     $message=$langs->trans("WarningInstallDirExists",DOL_DOCUMENT_ROOT."/install");