diff --git a/global_filter.storage.inc b/global_filter.storage.inc
index b6ef740..b3f0ebc 100644
--- a/global_filter.storage.inc
+++ b/global_filter.storage.inc
@@ -188,7 +188,7 @@ function global_filter_set_on_session($name, $value) {
     drupal_set_message(t('Global Filter: filter name empty. Cannot set value.'), 'warning');
     return FALSE;
   }
-  if (is_array($value)) {
+  if (is_array($value) && $value) {
     // For e.g., hierarchical select.
     $value = global_filter_array_flatten($value);
     if (empty($value)) {