Windows Vista is a major release of the Windows NT operating system developed by Microsoft as the direct successor to Windows XP, which was released in 2001. At the time, this 5-year gap was the longest time span between successive releases of Microsoft's Windows desktop operating systems. Development was finished on November 8, 2006, and over the following three months, it was released in stages to computer hardware and software manufacturers, business customers, and retail channels. On January 30, 2007, it was released globally and made available for purchase and download from the Windows Marketplace, the first release of Windows to be made available through a digital distribution platform.
Windows Vista introduced an updated graphical user interface and visual style dubbed "Aero," a new search component called "Windows Search," redesigned networking, audio, print, and display sub-systems, and new multimedia tools such as Windows DVD Maker among other changes. Windows Vista aimed to increase the level of communication between machines on a home network, using peer-to-peer technology to simplify sharing and media between computers and devices. Windows Vista included version 3.0 of the .NET Framework, allowing software developers to write applications without traditional Windows APIs. Windows Vista removed support for Itanium and devices without ACPI.
While these new features and security improvements garnered praise, Windows Vista received mixed reviews and was also the target of significant criticism, such as of its high system requirements, more restrictive licensing terms, lack of compatibility, longer boot time, and excessive authorization prompts from User Account Control. Due to these and other issues, Windows Vista saw lower initial adoption and satisfaction rates than Windows XP, and it is generally considered a market failure. However, Windows Vista usage did exceed Microsoft's pre-launch two-year-out expectations of achieving 200 million users, with an estimated 330 million Internet users in January 2009.