diff --git a/autoload.php b/autoload.php
index 2c21bb2d3e..8788be95b5 100644
--- a/autoload.php
+++ b/autoload.php
@@ -13,12 +13,12 @@
 
 $autoloader = include __DIR__ . '/vendor/autoload.php';
 
-if (!$autoloader) {
-  header('500 Internal Server Error');
-  print 'Dependencies error! The system cannot access some files in the <code>vendor</code> folder.<br/>' . PHP_EOL .
-        'Did you run <code>composer install</code>? You may also need to check the folder permissions.<br/>' . PHP_EOL .
-        'Refer to the <a href="https://www.drupal.org/documentation/install/download#git">the Drupal installation guide</a> for instructions on installing with Composer.' . PHP_EOL;
-  exit();
+if (!$autoloader || !class_exists('\Drupal')) {
+  if (PHP_SAPI !== 'cli') {
+    header('500 Internal Server Error');
+  }
+  print 'Failed to set up the autoloader. This can occur because composer install has not been run. Refer to https://www.drupal.org/docs/8/install/step-2-install-dependencies-with-composer for more information.' . PHP_EOL;
+  exit(1);
 }
 
 return $autoloader;
diff --git a/index.php b/index.php
index ae07f31842..750dc282dc 100644
--- a/index.php
+++ b/index.php
@@ -13,14 +13,6 @@
 
 $autoloader = require_once 'autoload.php';
 
-if (!class_exists('\Drupal')) {
-  header('500 Internal Server Error');
-  print 'Dependencies error! The system cannot access some files in the <code>vendor</code> folder.<br/>' . PHP_EOL .
-    'Did you run <code>composer install</code>? You may also need to check the folder permissions.<br/>' . PHP_EOL .
-    'Refer to the <a href="https://www.drupal.org/documentation/install/download#git">the Drupal installation guide</a> for instructions on installing with Composer.' . PHP_EOL;
-  exit;
-}
-
 $kernel = new DrupalKernel('prod', $autoloader);
 
 $request = Request::createFromGlobals();