The development of Windows Vista (codenamed Longhorn) began in May 2001, prior to the completion of Windows XP, and continued until November 8, 2006, when it was released to manufacturing. Windows Vista was then released generally to retail on January 30, 2007.
Background Microsoft originally expected to ship a minor release of Windows code-named "Longhorn" sometime in October 2003 as a minor step between Windows XP (codenamed "Whistler") and the next planned major release of Windows, code-named "Blackcomb". Longhorn was an allusion to this plan: While Whistler and Blackcomb are large ski resorts in British Columbia, Longhorn is the name of a bar between the two mountains that Whistler's visitors pass to reach Blackcomb.
Gradually, Windows Longhorn assimilated many of the important new features and technologies slated for Blackcomb, resulting in the release date being pushed back a few times. Many of Microsoft's developers were also re-tasked with improving the security of Windows XP. Faced with ongoing delays with Longhorn and concerns about feature creep, Microsoft announced on August 27, 2004, that it was making significant changes. Longhorn development started afresh, building on the Windows Server 2003 SP1 code-base, and re-incorporating only the features that would be intended for an actual operating system release. Some previously announced features, such as WinFS and NGSCB, were dropped or postponed.
After Longhorn was renamed to Windows Vista in mid-2005, an unprecedented beta-test program was started which involved hundreds of thousands of volunteers and companies. Between September 2005 and October 2006, Microsoft released regular Community Technology Previews (CTP) to beta testers and two release candidates to the general public. Development of Windows Vista concluded with the November 8, 2006 announcement of its completion by co-president of Windows development, Jim Allchin.
Build information Most pre-release builds of Windows (including Longhorn and Vista) were identified by a label that was always displayed in the bottom-right corner of the desktop, also called a watermark. The watermark would look like this (note that the following text below is left-aligned by default; this text is usually displayed right-aligned in the actual OS):
Higher build numbers didn't automatically mean that the latest features from every development team at Microsoft were included. Typically, a team working on a certain feature or subsystem would generate their working builds which developers would test with, and when the code was deemed stable, all the changes would be incorporated back into the main development tree at once. At Microsoft, several "Build labs" exist where the compilation of the entirety of Windows can be performed by a team. The lab in which any given build originated is shown as part of the build label, and the date and time of the build follow that.
In the case of above example (derived from Windows Longhorn build 3683), the name of the operating system ("Longhorn XP Professional") is displayed on the first row of the watermark, with the other text displayed underneath it containing the phrase "For testing purposes only" (indicating that a test certificate is installed in the build), and the build number, the name of the build lab, and the compile date of the build ("Build 3683.Lab06_N.020923-1821" means that the build of Windows Longhorn is 3683, compiled by the Lab06_N build lab on September 23, 2002 at 18:21 or 6:21 PM PDT).
Some builds (such as Beta 1 and Beta 2) only display the build label in the version information dialog (Winver), and the icons are from Windows XP. Most of the standard applets from Windows XP (including the Windows XP Tour applet) were retained in all pre-reset and most post-reset builds but were removed in later builds as the operating system was nearing completion. All pre-reset builds and some of the early post-reset builds still ran on the same SKUs as found on Windows XP but was changed to their final SKUs by the time the first publicly available version of the post-reset build of Longhorn was introduced.
The OOBE (the setup process) in the Milestone 3 builds is the same as Windows XP but with different music. It uses "No Hay Problema" by Pink Martini instead of the "Windows Welcome Music" composed by Stan LePard, which is also present in Windows Server 2003 but goes unused as the OOBE is not used in that operating system.
2001–2002: Early development (pre-reset builds)
The early development stages of Longhorn were generally characterized by incremental improvements and updates to Windows XP. During this period, Microsoft was fairly quiet about what was being worked on, as their marketing and public relations focus were more strongly focused on Windows XP and Windows Server 2003, the latter of which was released in April 2003. Occasional builds of Longhorn were leaked onto popular file sharing networks such as IRC, BitTorrent, eDonkey and various newsgroups, and so most of what is known about builds before the first sanctioned development release of Longhorn in May 2003, is derived from these builds.
Milestone 3 Build 3663 (Lab06_N) (build date of July 28, 2002) was the first known build with leaked screenshots. It shares a similar build number with Release Candidate 1 of Windows Server 2003 (then known as "Windows .NET Server" at the time), of which this build (and later builds in the "pre-reset" era) was built off of. Also, some screenshots of build 3670 (Lab06_N) (build date of August 19, 2002), which showed a version of Device Manager implemented into Windows Explorer (which later appeared in Windows 7), leaked.
Build 3683 (Lab06_N) (build date of September 23, 2002) was the first Windows Longhorn build leaked to the Internet (on November 19, 2002), and was the first of several that had a desktop watermark identifying itself as "Longhorn XP Professional". Visually very similar to Windows XP, one of the notable changes was that the Windows logo was only white, not colored like all the versions of Windows before it. Also the templates in the My Documents and My Pictures were notably different as well as the Open and Save as dialog boxes also included the template, incorporating aesthetic changes and a few new user interface options. A new "Sidebar" was also present, which contained many of the gadgets that would much later be seen in Windows Sidebar, such as an analog clock, slide show, and search capability. An option in this version of the sidebar also made it possible to move the Start button into it, and disable the traditional taskbar entirely. An early revision of WinFS was also included, but very little in the way of a user interface was included, and as such it appeared to early testers to be nothing more than a service that consumed large amounts of memory and processor time. The "Display Properties" control panel was the first significant departure, being built on the new "Avalon" API. It was the first sighting of the "Plex" style which Microsoft regarded as a placeholder theme for their development versions, until they were ready to demonstrate Aero.
Build 3706 (Lab06_N) (build date of October 29, 2002) was leaked on May 22, 2006. It was one of the first builds to include the Desktop Composition Engine (DCE), which later became the Desktop Window Manager (DWM). This build appeared on the Internet long after other builds from this period, and included several of the changes that were first reported as being part of later milestone builds, including Internet Explorer 6.05 and the "Plex" theme.
Build 3718 (Lab06_N) (build date of November 19, 2002) was leaked on April 20, 2004. It included the DCE and some early hardware-accelerated alpha transparency and transition effects. As a demonstration of the DCE's capabilities, programs flipped into the taskbar and twisted as they were minimized.
2003 and early 2004: New technology
Milestone 4 After several months of relatively little news or activity from Microsoft with Longhorn, build 4008 (main) (with a build date of February 19, 2003) made an appearance on the Internet on February 28, 2003. It was also privately handed out to a select group of software developers. This was the earliest known build of Longhorn to be built by the "main" branch as previous builds were built on the "Lab06_N" branch. As an evolutionary release over build 3683, it contained a number of small improvements, including a modified blue "Plex" theme and a new, simplified Windows Image-based installer that operated in graphical mode from the outset, and completed an install of the operating system in approximately one third the time of Windows XP on the same hardware. An optional "new taskbar" was introduced that was thinner than the previous build and displayed the time differently. This "new taskbar" also displayed taskbar buttons at the center rather than on the left, something that would eventually appear 18 years later with Windows 11.
The most notable visual and functional difference, however, came with Windows Explorer. The incorporation of the Plex theme made blue the dominant color of the entire application. The Windows XP-style task pane was almost completely replaced with a large horizontal pane that appeared under the toolbars. A new search interface allowed for filtering of results, searching for Windows help, and natural-language queries that would be used to integrate with WinFS. The animated search characters were also removed. The "view modes" were also replaced with a single slider that would resize the icons in real-time, in a list, thumbnail, or details mode, depending on where the slider was. File metadata was also made more visible and more easily editable, with more active encouragement to fill out missing pieces of information. Also of note was the conversion of Windows Explorer to being a .NET application.
Milestone 5 Build 4015 (main) (build date of March 28, 2003) was leaked to the Internet on April 25, 2003. Several features Microsoft had been working on were rolled into this build, such as a range of parental controls, a Windows logo moved and enlarged to the left side of the Start button, a lot of additional configurability for the sidebar (including being able to put it below the taskbar at the bottom of the screen), and the notion of "Libraries" (later known as virtual folders) of files. These libraries collected content from around the hard drive. The user could then filter this content and save it in a folder. Microsoft had originally intended to replace all special shell folders (My Documents, My Music, etc.) with virtual folders. However, this change was deemed too drastic and was dropped after Beta 1's release in mid-2005. Libraries were later included in Windows 7. This build was also notable for the debut of a simplified boot screen containing only the operating system logo and progress bar, which would resemble the one seen in the final release (though 4015's version of the progress bar was blue, not green (being largely similar to Windows XP); the final release also lacked an official logo and had the copyright infos placed underneath the progress bar). A new Download Manager shell location suggested that Internet Explorer would get a Mozilla-style download manager, though no such functionality was apparent. Significant memory leak problems with Windows Explorer and the Sidebar made this build difficult to use, which resulted in some third-party hacks to mitigate the problem. The back-end database of Outlook Express changed completely and became dependent on WinFS to store its e-mails. WinFS itself still had significant performance and memory usage issues, and so it became common for testers to disable WinFS entirely, thus rendering Outlook Express inoperative.