diff --git a/bin/dbmodel-files b/bin/dbmodel-files
index fd9d3a4..706c957 100644
--- a/bin/dbmodel-files
+++ b/bin/dbmodel-files
@@ -191,9 +191,9 @@ if ($suc) {
 function findProjectRoot(string $startDir): ?string
 {
 	$dir = realpath($startDir);
-
+	if (!$dir) return null;
 	while ($dir && $dir !== dirname($dir)) {
-		if (file_exists($dir . '/composer.json')) {
+		if (is_file($dir . '/vendor/autoload.php')) {
 			return $dir;
 		}
 		$dir = dirname($dir);