The Mac OS X 10.5.6 Update is recommended for Mac OS X 10.5 Leopard versions 10.5, 10.5.1, 10.5.2, 10.5.3, 10.5.4, and 10.5.5. It includes general operating system fixes that enhance the stability, compatibility and security of your Mac. Installation recommendations Back up your computer prior to installing any updates. Quit any open applications before starting the installation. Do not interrupt the installation process. You may experience unexpected results if you have third-party system software modifications installed, or if you have modified the operating system through other means, or if you have moved Apple applications from their default locations (the /Applications or /Applications/Utilities folders). (This does not apply to normal application software installation.) Installation options Automatic Software Update Choose Software Update from the Apple menu to automatically check for the latest Apple software. Standalone installer Apple Downloads offers a standalone installer that you can use instead, if you wish. If issues occur during installation or if Software Update unexpectedly quits, please visit this article.