diff --git a/plugins/views_plugin_cache.inc b/plugins/views_plugin_cache.inc
index ceef865..7579872 100644
--- a/plugins/views_plugin_cache.inc
+++ b/plugins/views_plugin_cache.inc
@@ -255,9 +255,11 @@ class views_plugin_cache extends views_plugin {
       $build_info = $this->view->build_info;
       
       foreach (array('query', 'count_query') as $index) {
-        $query = clone $build_info[$index];
-        $query->preExecute();
-        $build_info[$index] = (string)$query;
+        if (!empty($build_info[$index])) {
+          $query = clone $build_info[$index];
+          $query->preExecute();
+          $build_info[$index] = (string)$query;          
+        }
       }
       $key_data = array(
         'build_info' => $build_info,