diff --git a/config/routes.rb b/config/routes.rb
index 312f93a1c1e..c684da82fe7 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -7,7 +7,7 @@ require_dependency "homepage_constraint"
 # This used to be User#username_format, but that causes a preload of the User object
 # and makes Guard not work properly.
 USERNAME_ROUTE_FORMAT = /[A-Za-z0-9\_]+/ unless defined? USERNAME_ROUTE_FORMAT
-BACKUP_ROUTE_FORMAT = /\d{4}(-\d{2}){2}-\d{6}\.tar\.gz/i unless defined? BACKUP_ROUTE_FORMAT
+BACKUP_ROUTE_FORMAT = /[a-zA-Z0-9\-_]*\d{4}(-\d{2}){2}-\d{6}\.tar\.gz/i unless defined? BACKUP_ROUTE_FORMAT
 
 Discourse::Application.routes.draw do