Windows 2000 development had two apparently contradictory goals, to add functionality whilst improving dependability to the end customer. This paper describes the difficulty in developing the processes to characterizing the dependability goals for Windows 2000. The paper further describes how Windows 2000 met those goals through addition of dependability features and comprehensive testing in laboratories and production environments. These goals could not be achieved solely through improvements to the operating systems but also required addressing additional issues, such as improving the installation process and quality of driver software. The development of Windows 2000 highlighted a number of research opportunities, discussed later in the paper, to impact the development and release of highly dependable software.