diff --git a/core/lib/Drupal/Core/Config/Schema/Mapping.php b/core/lib/Drupal/Core/Config/Schema/Mapping.php
index 19fb596..c90ad1b 100644
--- a/core/lib/Drupal/Core/Config/Schema/Mapping.php
+++ b/core/lib/Drupal/Core/Config/Schema/Mapping.php
@@ -46,13 +46,13 @@ public function get($property_name) {
       $element = $elements[$root_key];
     }
     else {
-      throw new SchemaIncompleteException(String::format("The configuration property @key doesn't exist.", array('@key' => $property_name)));
+      throw new SchemaIncompleteException(String::format("The configuration property @key.@element doesn't exist.", array('@key' => $this->name, '@element' => $property_name)));
     }
 
     // If $property_name contained a dot recurse into the keys.
     foreach ($parts as $key) {
      if (!is_object($element) || !method_exists($element, 'get')) {
-        throw new SchemaIncompleteException(String::format("The configuration property @key does not exist.", array('@key' => $property_name)));
+        throw new SchemaIncompleteException(String::format("The configuration property @key.@element does not exist.", array('@key' => $this->name, '@element' => $property_name)));
       }
       $element = $element->get($key);
     }