diff --git a/includes/bootstrap.inc b/includes/bootstrap.inc
index 8c5b294..0ff8964 100644
--- a/includes/bootstrap.inc
+++ b/includes/bootstrap.inc
@@ -562,7 +562,7 @@ function drupal_get_filename($type, $name, $filename = NULL) {
  */
 function variable_init($conf = array(), $regenerate = FALSE, $recursion_depth = 0) {
   // NOTE: caching the variables improves performance by 20% when serving cached pages.
-  if (!$regenerate && $cached = cache_get('variables', 'cache')) {
+  if (!$regenerate && ($cached = cache_get('variables', 'cache')) && !empty($cached->data)) {
     $variables = $cached->data;
   }
   else {