diff --git a/includes/index_entity.inc b/includes/index_entity.inc
index ebda6cd..34e4b95 100644
--- a/includes/index_entity.inc
+++ b/includes/index_entity.inc
@@ -513,7 +513,8 @@ class SearchApiIndex extends Entity {
    *   The altered property info.
    */
   public function propertyInfoAlter(EntityMetadataWrapper $wrapper, array $property_info) {
-    if (entity_get_property_info($wrapper->type())) {
+    $entity_type = $wrapper->type();
+    if (!empty($entity_type) && entity_get_property_info($entity_type)) {
       // Overwrite the existing properties with the list of properties including
       // all fields regardless of the used bundle.
       $property_info['properties'] = entity_get_all_property_info($wrapper->type());