Microsoft Windows 10 Professional (x86) Build 10240 September 2015 (RTM).

Windows 10 is a personal computer operating system released by Microsoft as part of the Windows NT family of operating systems. It was officially unveiled in September 2014 following a brief demo at Build 2014. The first version of the operating system entered a public beta testing process in October 2014, leading up to its consumer release on July 29, 2015,[4] and its release to volume licensing on August 1, 2015. To encourage the adoption of Windows 10, Microsoft announced that during its first year of availability, the operating system would be made available free of charge to users of genuine copies of eligible editions of Windows 7 or Windows 8.1.

Windows 10 introduces what Microsoft described as a "universal" application architecture; expanding on Metro-style apps, these apps can be designed to run across multiple Microsoft product families with nearly identical code—including PCs, tablets, smartphones, embedded systems, Xbox One, Surface Hub and HoloLens. The Windows user interface was revised to handle transitions between a mouse-oriented interface and a touchscreen-optimized interface based on available input devices—particularly on 2-in-1 PCs; both interfaces include an updated Start menu that blends elements of Windows 7's traditional Start menu with the tiles of Windows 8. The first release of Windows 10 also introduces a virtual desktop system, a window and desktop management feature called Task View, the Microsoft Edge web browser, support for fingerprint and face recognition login, new security features for enterprise environments, and DirectX 12 and WDDM 2.0 to improve the operating system's graphics capabilities for games.

Microsoft described Windows 10 as an 'operating system as a service' that would receive ongoing updates to its features and functionality, augmented with the ability for enterprise environments to receive non-critical updates at a slower pace, or use long-term support milestones that will only receive critical updates, such as security patches, over their five-year lifespan of mainstream support. Terry Myerson, executive vice president of Microsoft's Windows and Devices Group, argued that the goal of this model was to reduce fragmentation across the Windows platform, as Microsoft aimed to have Windows 10 installed on at least one billion devices in the two to three years following its release.[5]

Windows 10 received mostly positive reviews upon its original release in July 2015; critics praised Microsoft's decision to downplay user-interface mechanics introduced by Windows 8 (including the full screen apps and Start screen) in non-touch environments to provide a desktop-oriented interface in line with previous versions of Windows, although Windows 10's touch-oriented user interface mode was panned for containing regressions upon the touch-oriented interface of Windows 8. Critics also praised the improvements to Windows 10's bundled software over 8.1, Xbox Live integration, as well as the functionality and capabilities of Cortana and the replacement of Internet Explorer with Edge—although the browser was criticized for being a work in progress that was not yet feature complete.
Windows 10 was also criticized for limiting how users can control its operation; in particular, Windows Update installs all updates automatically, no longer allows users to selectively install updates, and only the Pro edition of Windows 10 can delay the automatic installation of new builds of the platform. Privacy concerns were also voiced by critics and advocates, as the operating system's default settings and certain features require the transmission of user data to Microsoft or its partners. Microsoft has also received criticism for how it has distributed Windows 10—which has included the automatic downloads of installation files to computers without expressed user consent. Critics characterized the initial release of Windows 10 as being rushed, citing the incomplete state of some of the operating system's bundled software (such as the Edge web browser), as well as the stability of the OS itself on launch