Check your email confirmation from the Microsoft Store. Windows Vienna - Installation and Overview
Originally intended to follow Windows Vista, the "Vienna" project was Microsoft’s attempt to fix the performance and compatibility issues that plagued its predecessor. It began under the name "Blackcomb" before being rebranded as Vienna, and finally, simplified to Microsoft Dev Blogs Why You Won’t Find a "Vienna" Key windows vienna product key
Let’s cut through the noise immediately: Why? Because Windows Vienna was never released. It was a codename —and one that was discarded early in development. Check your email confirmation from the Microsoft Store
Since Vienna was an internal development codename, Microsoft never sold it in stores. The product keys issued during that era were for beta testers or early developers. If you are trying to activate a retail version of the software today, you actually need a 25-character Windows 7 key Microsoft Support How to Find Your Actual Product Key Because Windows Vienna was never released
Have a vintage Windows Vienna build running in a VM? Preserve that history responsibly. For further reading, explore the BetaArchive wiki or the Microsoft Collection Book. Stay curious, and stay safe.