diff --git a/core/modules/taxonomy/taxonomy.install b/core/modules/taxonomy/taxonomy.install
index 179aaeb..f579755 100644
--- a/core/modules/taxonomy/taxonomy.install
+++ b/core/modules/taxonomy/taxonomy.install
@@ -378,7 +378,10 @@ function taxonomy_update_8007() {
       }
 
       // Update the indexes in field config as well.
-      $field_config->set('indexes', array('target_id' => array('target_id')));
+      $indexes = $field_config->get('indexes');
+      unset($indexes['tid']);
+      $indexes['target_id'] = array('target_id');
+      $field_config->set('indexes', $indexes);
       $field_config->save();
     }
   }