First look: Microsoft is currently selling the idea of Windows and Copilot as two separate things: an OS and an assistant riding along on top of it. However, a leaked video shows Project Aion, an internal prototype where Copilot doesn't just sit inside Windows, it becomes Windows, swallowing the Start menu, the taskbar, and three decades of desktop conventions in the process. The footage is reportedly two years old, so Aion is most likely dead by now. But it's the clearest look yet at how far Microsoft was willing to take its agentic AI ambitions.
Back when Copilot was still a brand-new AI experience, Microsoft was already trying to turn the service into a cloud-based OS. That experiment appears to be long gone now, but Microsoft is apparently still trying to bring Copilot everywhere, despite stating otherwise.
The Aion clip first leaked through BetaWiki's Discord server, describing a web-based agentic OS with the Copilot AI baked directly into the system's core shell. The system runs on "Win3," a supposedly new Windows codebase designed to be lightweight and entirely web-based. The Edge browser, and by extension Chromium's layout engine, serves as the shell powering Copilot's new AI experience.
Aion includes a multi-modal input box, where users can type textual queries to instruct Copilot to do its thing. There's also a stub for Taskbar and Start Menu-like functionality, plus a new "Spaces" concept where "apps" and websites get grouped together by the AI. Spaces can be closed and recalled with ease through the Start Menu-like interface at any time.
Since Win3-based Project Aion relies mostly on web technologies, there appears to be no native support for traditional Win32 applications. When users need to launch a Win32 program such as Word, Aion instead provides a link to a Windows Cloud PC instance to safely (and virtually) run that program remotely.

Other Aion features include "rich" plugins designed to interact with Copilot, adding functionality like sending an Outlook email to a coworker directly from the multi-modal box. Needless to say, the AI will gladly draft that email based on the content available in that specific Space.
Sources confirm the video clip is real, despite being two years old. Since no detailed or "official" information is available about Aion, we still don't know if the agentic OS was just a "hacking" experiment put together by a Microsoft internal team or a real product idea.

After an initial push to insert the Copilot experience into every corner of Windows 11, Microsoft now appears to be backing away from that plan. Users have mostly reacted negatively to Aion's leaked clip, and Microsoft itself has confirmed, in its own terms of use, that customers should use Copilot at their own risk.
And yet Copilot is still spreading into countless new agentic "personas," while the Edge browser can already perform some of the agentic tasks Aion was designed to deliver within a web-based shell.