This clip comes from Windows 10 Build 10074, an early Insider Preview version of Microsoft's operating system released in 2015, when the new calendar and notification system was still taking shape. The short chime was designed to alert users to upcoming appointments without interrupting their work, a purpose reflected in its gentle tone. Today it survives mainly through soundboard archives and retro computing collections, where people save old system sounds that were replaced in later Windows releases. Its appeal lies in that brief window of Windows history, before the final version standardised its alerts.