For buyers contracting authority
Choose 48624000 when the operating system targets ordinary PCs, the desktops and laptops your staff use, rather than another class of machine. The sibling codes exist precisely to keep machine classes apart: a mainframe OS is 48621000, a minicomputer OS is 48622000, a microcomputer OS is 48623000, and open-systems operating systems sit at 48625000.
The practical trigger is the estate. Contracting authorities reach for this code when they are licensing or relicensing the operating system across a fleet of PCs, very often as part of a Microsoft enterprise or framework agreement that also sweeps in productivity software, server access and support. That bundling is the norm here, not the exception, and it is visible in the award titles below.
This creates a tagging judgement call. When a single contract licenses the PC operating system alongside office software, server access licences and cloud subscriptions, set the primary CPV code by whichever element is the dominant purpose. Where the operating-system estate genuinely leads, 48624000 fits. Where the office suite or a broader software bundle leads, a more general software-package or licensing code is the better primary tag.