Despite these shortcomings, 60 million Windows 8 licenses were sold through January 2013, a number that included both upgrades and sales to OEMs for new PCs. Although reaction towards its performance improvements, security enhancements, and improved support for touchscreen devices was positive, the new user interface of the operating system was widely criticized for being potentially confusing and difficult to learn, especially when used with a keyboard and mouse instead of a touchscreen. Windows 8 was released to a mixed critical reception. Windows 8 removed support for non- SSE2 CPUs and devices without NX. Windows 8 is the first version of Windows to support the ARM architecture, under the Windows RT branding. Additional security features were introduced, such as built-in antivirus software, integration with Microsoft SmartScreen phishing filtering service and support for UEFI Secure Boot on supported devices. Windows 8 added support for USB 3.0, Advanced Format hard drives, near field communications, and cloud computing. Many of these features were adopted from Windows Phone. In particular, these changes included a touch-optimized Windows shell based on Microsoft's Metro design language and the Start screen, a new platform for developing apps with an emphasis on touchscreen input, integration with online services, and Windows Store, an online distribution for downloading and purchasing new software, and a new keyboard shortcut for screenshots.

Windows 8 introduced major changes to the operating system's platform and user interface intended to improve its user experience on tablets, where Windows was now competing with mobile operating systems, including Android and iOS.

It was released to manufacturing on Augit was subsequently made available for download via MSDN and TechNet on August 15, 2012, and later to retail on October 26, 2012. Windows 8 is a major release of the Windows NT operating system developed by Microsoft.

Windows 8 serial number 22