Reactions to Microsoft’s release of their Windows operating systems have followed a predictable pattern for decades. Users rightly bemoan its lack of long-awaited features, or decry its gaping security holes. Industry experts and critics use those user reactions to predict the beginning of the end of Windows, if not for all of Microsoft. But in the end sales of the operating system beat not only expectations, but all all previous records. Such exactly was the case with Windows XP.

On this day, October 25, in 2001, Windows XP was released to retailers worldwide. Its redesigned interface included more user-friendly features and for the first time built-in CD burning software.

Windows XP was criticized for its lack of security. With more machines having a near-constant connection to the Internet, the vulnerabilities greatly increased. Microsoft eventually released a total of three Service Pack updates to plug some of those holes. Despite the criticisms, XP sold 400 million units within several years, and at its height in 2007, three out of every four machines connected to the Internet were Windows-powered.