diff --git a/scripts/composer/ScriptHandler.php b/scripts/composer/ScriptHandler.php
index 7a473f1b7..a5b8d36be 100644
--- a/scripts/composer/ScriptHandler.php
+++ b/scripts/composer/ScriptHandler.php
@@ -22,7 +22,10 @@ public static function createRequiredFiles(Event $event) {
     $drupalFinder = new DrupalFinderComposerRuntime();
     $drupalRoot = $drupalFinder->getDrupalRoot();
 
-    // If Drupal root was not found, exit.
+    if (is_null($drupalRoot)) {
+      $event->getIO()->writeError('<error>Drupal root could not be detected.</error>');
+      exit(1);
+    }
     if (is_null($drupalRoot)) {
       $io = $event->getIO();
       $io->writeError(