An iPad displays a screenshot of the Cortana OS Start menu.

Design decisions in Cortana OS

Explaining some of the design decisions in the Cortana OS project.

January 27, 2019

This weekend, I posted some initial mockups for a project called “Cortana OS” to Twitter. Character limits make it hard for me to convey everything I want to, so I wanted to write this short post explaining some of the design decisions that went in to this.

The name

Cortana OS

Yeah, I guess it sounds weird at the moment. It’s a working title and I’ve been suggested some different names, but let me explain why it isn’t called Windows.

This product, while following the same design language as Windows, isn’t Windows. It’s something completely new. Windows RT and the later Windows 10 S both suffered because they were branded as “Windows”. People expected it to do everything their classic Windows laptop/desktop did.

Calling this product something entirely new helps break away from that expectation.

Rounded corners

The Mail app in Cortana OS shows how rounded corners are used throughout the design.

Doesn’t this go against Microsoft’s whole modern design language?


But also maybe not. Tying back to the product name, Cortana’s persona is a circle. She’s bubbly and fun. And so is this product.


In Cortana OS, the Start menu can be accessed by swiping up from the bottom of any screen.

There’s no taskbar in the tablet mode of Cortana OS, so how do you get back to Start, or move between apps, or display notifications?


Sliding up from the bottom edge displays the Start overlay, no matter where you are in the product. From here you can quickly launch into a new app, search the device/web, or access your Timeline. Sliding down from the top triggers the multitasking view–a grid of the apps you have open with the ability to drag and drop them into a snapped view. Sliding from the right brings the familiar Action Center.

Other loose ends

The keyboard is powered by the same SwiftKey intelligence as on Windows 10 and includes gestural typing.

“It looks like the Surface Hub 2X’s operating system”

Surface Hub 2X did serve as an inspiration for the Start screen of Cortana OS, however instead of displaying the Timeline view first, pinned apps are displayed.

“What about the desktop?”

A desktop mode exists and allows you to run apps inside windows, but it’s much simpler than the desktop today on Windows 10.

“Where are the Live Tiles?”

As reported by Windows Central last week, it’s looking like Microsoft’s upcoming “Windows Lite” doesn’t include Live Tiles. I can understand why, users can be confused when their app icons seemingly keep changing. Because of the news that Lite may ditch tiles in favor of static icons, I’ve done the same.


Project Meta

Unfinished Projects

Microsoft Edge for iOS redesign