diff --git a/htdocs/core/lib/barcode.lib.php b/htdocs/core/lib/barcode.lib.php
index f0604400525..702d6673527 100644
--- a/htdocs/core/lib/barcode.lib.php
+++ b/htdocs/core/lib/barcode.lib.php
@@ -59,6 +59,7 @@ if (empty($font_loc)) {
 if (defined('PHP-BARCODE_PATH_COMMAND')) {
 	$genbarcode_loc = constant('PHP-BARCODE_PATH_COMMAND');
 } else {
+	$genbarcode_loc = '';
 	if (!empty($conf->global->GENBARCODE_LOCATION)) {
 		$genbarcode_loc = $conf->global->GENBARCODE_LOCATION;
 	}