diff --git a/validate.php b/validate.php
index a3e6c505f6..ec90514375 100755
--- a/validate.php
+++ b/validate.php
@@ -65,6 +65,10 @@ register_shutdown_function(function () {
     global $precheck_complete;
 
     if (!$precheck_complete) {
+        // use this in case composer autoloader isn't available
+        spl_autoload_register(function($class) {
+            include str_replace('\\', '/', $class) . '.php';
+        });
         print_header(version_info());
     }
 });