diff --git a/app/controllers/settings_controller.rb b/app/controllers/settings_controller.rb
index e9bc0a60..7d99a726 100644
--- a/app/controllers/settings_controller.rb
+++ b/app/controllers/settings_controller.rb
@@ -40,7 +40,7 @@ class SettingsController < ApplicationController
     @options[:user_format] = User::USER_FORMATS.keys.collect {|f| [User.current.name(f), f.to_s] }
     @deliveries = ActionMailer::Base.perform_deliveries
 
-    @guessed_host_and_path = request.host_with_port
+    @guessed_host_and_path = request.host_with_port.dup
     @guessed_host_and_path << ('/'+ Redmine::Utils.relative_url_root.gsub(%r{^\/}, '')) unless Redmine::Utils.relative_url_root.blank?
   end