diff --git a/src/cli/flow b/src/cli/flow
index 0e549194c..d252972b6 100644
--- a/src/cli/flow
+++ b/src/cli/flow
@@ -10,7 +10,17 @@ use Symfony\Component\Console\Application;
 if ('' !== Phar::running(false)) {
     require 'phar://flow.phar/vendor/autoload.php';
 } else {
-    require __DIR__ . '/../vendor/autoload.php';
+    if (\is_file(__DIR__ . '/vendor/autoload.php')) {
+        $autoloader = require __DIR__ . '/vendor/autoload.php';
+    } elseif (\is_file(__DIR__ . '/../vendor/autoload.php')) {
+        $autoloader = require __DIR__ . '/../vendor/autoload.php';
+    } elseif (\is_file(__DIR__ . '/../../../autoload.php')) {
+        $autoloader = require __DIR__ . '/../../../autoload.php';
+    } else {
+        echo 'Cannot find the vendor directory, have you executed composer install?' . PHP_EOL;
+        echo 'See https://getcomposer.org to get Composer.' . PHP_EOL;
+        exit(1);
+    }
 }
 
 if (false === \in_array(PHP_SAPI, ['cli', 'phpdbg', 'embed'], true)) {