Microsoft OS Prototype Project Aion Leaked, Revealing Copilot-Centered Interface

Internal documents that have been leaked and a video have shown that Project Aion was an experimental project carried out by Microsoft for 2024 or earlier in which Copilot was placed at the heart of the interface.

The material describes a web-based prototype that is operational and has been built using a modified form of Microsoft Edge together with a lightweight Windows codebase known as Win3 within the company.

The documents that have leaked show the name CopilotOS and describe a plan under which Copilot would become the primary means by which people communicate, find entertainment, learn and carry out various tasks. Microsoft has refused to comment on the project. The leaked material does not prove that Project Aion is a product which Microsoft intends to launch.

Project Aion Replaced the Windows Shell With Copilot

During the Win3 demonstration, Project Aion was run without the usual Windows Start menu, desktop icons, or the apps that were pinned to the taskbar. Copilot served as the primary launcher and the shell operated via Edge, using web technology for apps, websites, and system tasks.

When the Copilot button was clicked, a dashboard appeared and greeted the demo user with "Good afternoon, Nathan". This dashboard displayed three cards, one for Stay on Top, one for Create something new, and one for News of the day.

There was also a My Stuff section which included Edge, Teams, Outlook, OneDrive, and Microsoft 365, as well as Figma and Visual Studio Code.

The internal document referred to Aion as an "Agent/Copilot OS" designed to operate on AI-oriented devices running AOSP, Win3, or Windows 11, AOSP being the open-source foundation of Android; another internal description termed Aion "a portable, web-shell" developed using a modified Edge and connected to Windows 365 in order to provide full access to the Windows desktop.

Because of its cross-platform design, Aion could function as a replacement shell on either Windows 11 or on AOSP Android; Win3 was a separate and lighter version of the Windows codebase, which was intended to provide faster startup times, longer battery life, and better security, though it did not support legacy applications.

The "Ask me anything" field in Aion was the primary method for opening applications, browsing the web, and beginning tasks; for example, typing in "techc" would suggest TechCrunch, while typing "to do" would display Microsoft To Do in a floating Edge picture-in-picture window rather than launching the native Windows application.

The interface was altered for more complicated requests; for example, when asking about dining facilities in Maui a floating Copilot chat appeared showing the names of restaurants and travel links, and when asking about meetings for the following Monday another chat window opened alongside it.

The taskbar icon for each conversation was based on its topic rather than using another Copilot symbol; the dining chat for Maui had a martini-glass icon, the meeting chat had a calendar icon, and when a chat was closed it was saved as a chip under My Stuff so that the task could be reopened later.

Project Aion's Spaces, Microsoft 365 Integration, and Desktop App Limits

There was a feature named Spaces which grouped together apps, websites, files, and conversations according to their purpose. For instance, the TURKEY TRIP feature had a Description and Goals card for planning a trip to Turkey in September, a Personal topic setting, a creative conversation style, and also included entries for Edge, WhatsApp, YouTube, Word, Turkish Airlines, Expedia, and Airbnb; it also contained a Draft an itinerary action, and its Contents section had tabs labeled Recents and Suggested.

The parts of Aion relating to work were directly linked to information in Microsoft 365. For example, when a query about Scott Schenone was made, Copilot searched both SharePoint and email, recognized him as a Senior Design Director involved in the Lanai project, and then provided a summary of his recent work based on the internal documents.

When a forward slash is typed into the search box, Context IQ appears and displays the relevant colleagues and files from Microsoft 365 ready to be included in the prompt.

Additionally, Copilot was able to draft an email within an Outlook-style compose window, featuring tone controls marked Casual, Professional, Funny, and Undead Pirate Captain, before sending the message without having to open Outlook.

Edge also allowed Aion to gain access to the underlying HTML of websites through a process that Microsoft referred to as DOM crawling. The leaked documents described this as involving the reading of the page structure in order to understand content that is not visible on the screen.

The version of Win3 that was leaked was unable to run traditional Win32 desktop applications native to the system. In the case of a task that required a full desktop application, Aion would ask the user to use Microsoft's Windows 365 Cloud PC service, providing a streamed Windows session with the document already open and the Copilot Summary panel available.

The restriction appeared when an Excel demo was used, this being a table that compared the square footage of different property listings. Aion responded by saying, "I'm sorry, I can't open Excel for you," then created the comparison within the chat, provided a download link that worked, directed the user to the Excel progressive web app, and displayed a "Suggested tools: Excel" chip.

The design was not just a typical desktop layout; one leaked document illustrated three different setups: Landscape with Docked Conversation, Portrait with Docked Conversation, and Soft Keyboard.

In a research task carried out at a Maui dive shop, the approach was adapted to a tablet-style portrait view together with an on-screen keyboard. Moreover, Aion's address field functioned as an omnibox, and when "maui" was typed, it displayed location-aware suggestions and filters for Microsoft, History, Favorites, and Tabs.

How Project Aion Connects to Microsoft's Public Windows AI Plans

Microsoft has carried on with its public work on Windows by releasing Windows 11; in November 2025 the company began testing AI agents on the Windows 11 taskbar via Ask Copilot.

This involved displaying progress information on the taskbar and providing access to agents such as the Researcher in Microsoft 365 Copilot; the tasks carried out by these agents make use of Microsoft's dedicated Agent Workspace for Copilot Actions, this workspace running separately from the user's primary Windows session.

Microsoft has likewise continued its work on the standard components of the Windows interface, for example with the customizable context menu for Windows 11 and by transferring some of the core Windows features to WinUI 3. The company has also improved the performance of File Explorer, the Start menu, and other parts of Windows 11.

On March 20, 2026, Microsoft stated in a Windows quality update that it was eliminating unnecessary Copilot entry points, beginning with those in the Snipping Tool, Photos, Widgets, and Notepad. At the moment, the company's emphasis is on performance, reliability, interface quality, personalization, and the more selective use of AI features.

The leaked documents do not indicate that Project Aion is one of those products which Microsoft intends to release; the prototype was part of an incubation programme in 2024, achieved working code, and was experimental.

Its current status is unknown, and Microsoft declined to comment after the leak. It is not confirmed whether any Aion ideas will reach a shipping product or how they might connect to Microsoft's ongoing Windows 11 and Copilot work.

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