diff --git a/src/configuration/ArcanistConfiguration.php b/src/configuration/ArcanistConfiguration.php
--- a/src/configuration/ArcanistConfiguration.php
+++ b/src/configuration/ArcanistConfiguration.php
@@ -31,7 +31,13 @@
       $command = 'version';
     }
 
-    return clone idx($this->buildAllWorkflows(), $command);
+    $workflow = idx($this->buildAllWorkflows(), $command);
+
+    if (!$workflow) {
+      return null;
+    }
+
+    return clone $workflow;
   }
 
   public function buildAllWorkflows() {