diff -u b/includes/bootstrap.inc b/includes/bootstrap.inc
--- b/includes/bootstrap.inc
+++ b/includes/bootstrap.inc
@@ -887,8 +887,10 @@
       }
       catch (Exception $e) {
         // The database table may not exist because Drupal is not yet installed,
-        // or the database might be down. We have a fallback for this case so we
-        // hide the error completely.
+        // the database might be down, or we may have done a non-database cache
+        // flush while $conf['page_cache_without_database'] = TRUE and
+        // $conf['page_cache_invoke_hooks'] = TRUE. We have a fallback for these
+        // cases so we hide the error completely.
       }
     }
     // Fall back to searching the filesystem if the database could not find the