List of Microsoft codenames

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286DOS

OS/2 1.0, Microsoft naming

6 on 6

Windows Mobile 6.1.4

A

ADOS

OS/2 1.0

Advanced Windows

The original announced name for NT-based Windows, see Razzle

Akebono

Xbox Controller S

Alder

Windows CE 1.0

Anaconda

Xbox Series X

Andromeda

Canceled phone variant of Windows Core OS

Surface Pocket (cancelled Surface model designed to run Andromeda OS)

Another Fucking Driver

Ancilliary Function Driver (afd.sys)

Application Framework eXtensions

Microsoft Foundation Class Library

Apollo

Windows Phone 8

ASP+

ASP.NET

Arcata

Surface Pro 9 (5G)

Aruba

Surface Hub OS; see Lhok Sukon (LSX)

Argo

Zune

Aspen

Visual Studio 6.0

Asteroid

Windows 2000 Service Pack 1

Astro

MS-DOS 6

Canceled Microsoft Lumia phone model. Utilized a Qualcomm Snapdragon 820 (MSM8996) SoC.

Athens

Windows 10 IoT Core; named after the capital city of Greece

Aurora

Windows Small Business Server 2011 Essentials

Avalon

Windows Presentation Foundation

Azalia

Surface Laptop 6 for Business (15-inch)

B

Barrett

Windows 365 Link

Blackcomb

Planned successor of Windows XP and later Longhorn/Vista; named after Whistler Blackcomb, a ski resort in British Columbia popular among Microsoft executives

Birch

Windows CE 2.0

BirchWay

Surface Pro 9 (Intel)

Big Rock

Surface Laptop 7

BlackRock

Windows Dev Kit 2023

Blue

Windows 8.1

Windows Phone 8.1

Bobcat

Windows Small Business Server 2003

Bobsled

Internal name for Windows Media Center Extender devices

Boston

Visual Studio 5.0

Breckenridge

Windows Storage Server 2008 R2 Essentials

Brooklin

Xbox Series X refresh, scheduled to be released in 2024

Bulletproof

Microsoft mail remote client

C

Cairo

Canceled successor of Windows NT 3.x that aimed to implement Bill Gates' "Information at your fingertips" vision

Cairo Domains

Active Directory

Cairo Messaging

Microsoft Exchange

CairOLE

OLE 3.0

Callaway

Windows Dev Kit 2023

Cambria

Surface Pro X (SQ1)

Carina

Surface Pro X (SQ2)

Catapult

Microsoft Internet Information Server

Cascades

Canceled successor to Windows Essential Business Server 2008 based on Windows Server 2008 R2.

Cascadia

Windows Terminal; also used as the name of the Cascadia Code and Mono typefaces, designed for the Terminal

Cashmere

Word for Windows (later renamed to Opus)

Cassini

Windows Embedded 8

Caspar

Surface Pro X (Wi-Fi)

Cedar

Windows CE 3.0

Centaurus

Surface Neo

Centro

Windows Essential Business Server 2008

Charles de Gaulle, CDG

Windows 10X

Chelan

Windows Embedded Compact 7

Cherry Hill

Windows 11 shell experience pack updated via the Store

Chicago

Windows 95

Chucky

Windows 10 IoT Core shell

Cityman

Lumia 950 XL

Cleveland

Alternative name for a canceled successor of Windows 95, more commonly known as Nashville

CMERGE

Microsoft C 3.0, the first version of the C-branded compiler written by Microsoft (merging a separate Xenix C compiler, the backend of their Compiled BASIC product, and the licensed Lattice C Microsoft was selling for the IBM PC)

CloudDB

The first version of SQL Server that ran on Microsoft Azure (internally version 10.25)

Cobalt

The 21H2 (second half of 2021) engineering semester of Windows as a service; the base for the original release of Windows 11

Colorado

Windows Small Business Server 2011

Control Program/DOS, CP/DOS

OS/2 1.0; follows IBM mainframe product naming

Copper

The late 2022 engineering milestone of Windows as a service

CorePC

Alleged successor to Windows Core OS. Provides a modular operating system base targeting different system form factors

Corona

Windows Media Player 9 Series

Xbox 360 S motherboard revision (2011-2012)

Cougar

The 32-bit DOS kernel in Windows 95 (DOS386.EXE/VMM32.VXD)

Windows Small Business Server 2008

Crescent

Windows Media Player 10

Cronos

Canceled Microsoft Surface Duo model. Utilized a Qualcomm Snapdragon 778G 5G (SM7325) SoC.

Crossbow

Windows Mobile 6.0

Cruiser

OS/2 2.0

Cupcake

Internal Windows componentization effort featuring 5 layers, related to CorePC

Cutter

OS/2 1.3

D

Dallas

SQL Server 2012

Darwin

Windows Installer

Daytona

Windows NT 3.5

Denali

Active Server Pages

SQL Server 2012

Deschutes

Windows 365 Cloud PC

Detroit

USB supplement update for Windows 95 OSR2

Diamond

Windows Media Center UI overhaul for Windows Vista

Dilithium

The early-2024 engineering milestone of Windows as a service. Named after the fictional material from Star Trek, as arsenic is infamous for its use in poisons.

DirectX Box

Xbox

Doesn't Matterhorn

Pre-reset Windows Vista

DOS 5.0

OS/2 1.0; name used primarily by Microsoft – implies that OS/2 is the successor to the multitasking MS-DOS 4.

The Duke

Xbox controller

Durango

Xbox One

E

Edmonton

Xbox One S

eHome

Windows Media Center

Eiger

Windows Fundamentals for Legacy PCs

Electronic Paper

The original concept for Excel

Ellewood

Xbox Series S refresh, scheduled to be released in 2024

Elmer

Surface Laptop Studio 2

Elroy

Windows Live Mail

Emerald

Windows XP Media Center Edition 2005 Update Rollup 2

Epsilon

Surface Duo (after it was decided that the device would use Android instead of the cancelled Andromeda, and it was renamed)

Ersa

Surface Laptop Studio 2

Ersa Refresh

Surface Laptop Studio 3

Everett

Visual Studio .NET 2003

Escher

Visual Basic for MS-DOS

Ethos

Surface Duo

Excalibur

SQ SoC

F

Falcon

Xbox 360 Fat motherboard revision (late 2007-2008)

Fastbike

Fast boot in Windows Neptune (Profile Accelerated Boot Accelerator)

Fiji

Windows Vista Media Center TV Pack

Filipi

SQL Server 1.0

Firesteel

Internal Windows 11 self-hosting effort

Firebird

Cancelled update for Windows 10 Team

Football

OS/2 1.0–era multiple virtual DOS machines prototype using the virtual 8086 mode (previously known as Pigskin)

Forms³

Original IE layout engine, before Trident, later used in Office 2002.

Freestyle

Windows XP Media Center Edition

Frosting

Microsoft Plus! Companion for Windows 95

Fusion

Windows Side-by-Side Component Store (WinSxS)

.NET Framework CLR Loader

G

Galileo

Windows CE 3.0

Gallium

The mid-2023 engineering milestone of Windows as a service

Game SDK

DirectX

Gandalf

Encarta Multimedia Encyclopedia (original 1993 release)

Gemstar

WebTV for Windows

GeorgeTown

Surface RT

GeorgeTown X

Surface Pro

Germanium

The late-2023 engineering milestone of Windows as a service; the base for the Windows 11 2024 Update

Grendel

Surface Laptop 3 (AMD)

Guilin

Canceled Microsoft Lumia phone model. Utilized a Qualcomm Snapdragon 210 (MSM8909) SoC.

Gulliver

Surface Laptop Go 3

H

Haiku

Modular Windows

Hapanero (RX-130)

Engineering Board used by Microsoft during Windows 10 Mobile development. Utilized a Qualcomm Snapdragon 810 (MSM8994) SoC.

Harmony

Windows XP Media Center Edition 2004

Harvest

Surface Pro X (Wi-Fi)

Hekaton

SQL Server 2014

Helsinki

SQL Server 2016 (named after the capital of Finland

Hobart

Surface Pro X (SQ1)

Honjo

Canceled Microsoft Lumia phone model. Utilized a Qualcomm Snapdragon 210 (MSM8909) SoC.

Honolulu

Windows Admin Center

Hudson Valley

Rumored successor of Windows 11

Hydra

Windows NT Server 4.0, Terminal Server Edition

SQL Server 6.5

I

Idaho

Unrealized successor of Windows XP

Immersive Launcher, Immersive Shell

Start screen

Impala

Windows NT Embedded 4.0

Indi

Surface Laptop 5

Indigo

Windows Communication Foundation

Interface Manager

Internal UI library used by the Microsoft Apps team, merged with the Graphics Device Interface to create the project that led to Windows 1.0

Iron

The 21H1 (first half of 2021) engineering semester of Windows as a service; the base for Windows Server 2022

Iris

Surface Mini

J

Jaguar

The 16-bit MS-DOS subsystem in Windows 95. A standalone retail release was also planned at one point, which ultimately ended up not materializing

Jamdani

Journal user interface in Windows Andromeda OS

Jameson

Windows CE 4.1

Janus

Combined bundle of Windows 3.1 and MS-DOS 5

Canceled 64-bit port of Windows 2000 for Itanium-based systems

Jasper

Xbox 360 Fat motherboard revision (2008-2009)

Jastro

Combined bundle of Windows 3.1 and MS-DOS 6; portmanteau of Janus and Astro

Jazz

Computer architecture based on the MIPS R4000 processor

Juneau

SQL Server 2012 Developer Tools

Jupiter

Windows CE 2.0

Windows Runtime

K

Katmai

SQL Server 2008

Kilimanjaro, KJ

SQL Server 2008 R2

Kryptos

Xbox One

L

Lancelot

Surface Laptop and Surface Laptop 2

Lhok Sukon, LSX

Surface Hub OS; internally codenamed after the airport of the same name, intended for the cancelled Surface Hub 2X

Liberty

The 64-bit Edition of SQL Server 2000

Lifeboat

MS-DOS 5

Linares

Surface Thunderbolt 4 Dock

Lite

Windows 10X

Lockhart

Xbox Series S

Lonestar

Windows XP Tablet PC Edition 2005

Longhorn

Windows Vista, Windows Server 2008; named after a bar situated between the Whistler and Blackcomb mountains.

M

Macallan

Windows CE 5.0

Magneto

Windows Mobile 5.0

Malwa

Surface Laptop 6 for Business (13.5-inch)

Manganese

The 20H2 (second half of 2020) engineering semester of Windows as a service

Mango

Windows Phone 7.5

Mantis

Windows XP Embedded

Mars

Application framework used in Activity Centers, and the Help and Support Center in Windows Me and Windows XP

McKendric

Windows CE 4.2

Memphis

Windows 98

Merlin

Pocket PC 2002

Millennium

Windows Me

ModernPC

Cancelled internal effort that attempted to bring Windows Core OS onto varying consumer and business hardware platforms via multiple "personalities", e.g.: Windows 10X (CDG), Surface Hub OS (LSX), Santorini (JTR)

MoGo

Start screen

MoSh (Modern Shell)

Windows 8 user interface

Mojave

Fictitious release of Windows that was in fact a rebranded Windows Vista, which was the subject of a Microsoft case study known as the Mojave Experiment

Monaco

Visual Studio Code; adopted as the name of the Monaco Editor, the code editor component of Visual Studio Code decoupled for use in other applications

Monad

PowerShell

Monarch

Outlook progressive web application

Monica

Surface Pro 11

Monkton

Windows Dev Kit 2023

Monza

Surface Neo

MT-DOS

Multitasking MS-DOS 4

N

Nashville

Internet Explorer 4; originally referred to a canceled successor of Windows 95.

Nemesis

Windows Media Encoder 7.0

Neon

Fluent Design System, see Project Neon

Neptune

Canceled NT-based successor of the Windows 9x series; project merged with Odyssey in early 2000 to form Whistler. Sometimes stylized as NepTune.

NewShell

Shell Technology Preview; a series of updates for Windows NT 3.51 that backport the Windows 95 user interface

Nickel

The 2022 engineering milestone (also referred to as 22H2) of Windows as a service; the base for the Windows 11 2022 Update

NoDo

Windows Phone 7 March 2011 update

Northstar

Canceled Nokia Lumia model based upon the Qualcomm Snapdragon 820 (MSM8996) SoC

NT OS/2, NTOS

NT-based rewrite of OS/2 canceled in favor of Windows NT, see Razzle

NT Windows

Alternative name for Windows NT before that name was standardized, see Razzle

NXT

Windows 365 Link

Nyx

Surface Pro 3

O

O'Hare

Internet Explorer 1; named after the international airport near Chicago, the codename for Windows 95.

Oasis

Windows Holographic for Hololens 2

Odyssey

Unrealized successor of Windows 2000; project merged with Neptune in early 2000 to form Whistler.

Omega

Early version of Microsoft Access

Omega-13

Longhorn development reset; named after the time travel device of the same name seen in Galaxy Quest's climax, which sends the user exactly thirteen seconds back into the past

One Outlook

Outlook progressive web application

Opus

Word for Windows

Orca

SNA Server 3.0

Orcas

Visual Studio 2008

OS/2 3.0

NT-based rewrite of OS/2 canceled in favor of Windows NT, see Razzle

Ozone

Windows Mobile 2003

P

Panther

A short-lived lightweight fork of the Windows NT kernel for use in a consumer 32-bit version of Windows

Windows Deployment Services - WIM-based Windows Setup

Pegasus

Windows CE 1.0

Photon

Windows Phone 7

Pietro

SQL Server 1.1

Pigskin

OS/2 1.0–era multiple virtual DOS machines prototype using the virtual 8086 mode (early name for Football)

OS/2 2.0 (early name for Cruiser)

Pinewood

Surface Pro X

Polaris

Canceled desktop variant of Windows Core OS, intended for low-cost computers

Plato

SQL Server 7.0 Online Analytical Processing Tools suite

Portable OS/2

NT-based rewrite of OS/2, see Razzle

Porthole

Windows Libraries for OS/2

Portico

Windows Phone 8 GDR1

Potosi

Windows 365 Link

Project Neon

Fluent Design System

Project Reunion

Windows App SDK

Protogon

ReFS

Q

Quartz

ActiveMovie

Q, Quattro

Windows Home Server

Quebec

Windows Embedded Standard 7

R

Rainier

Visual Studio .NET (2002)

Rapier

Pocket PC 2000

Razzle

Windows NT 3.1; originally a rewrite of OS/2 based on the new NT kernel design, which was canceled with the IBM-Microsoft split in favor of Windows NT; kept as the name of the Windows NT build environment

Ren

Outlook; named after the fictional chihuahua cartoon character of the same name from The Ren & Stimpy Show

Redstone

Windows 10 Anniversary Update through October 2018 Update; named after the Redstone mineral from Minecraft.

REO Speedwagon

Unknown effort relating to giving the 16-bit Windows kernel the ability to enable and disable itself at will. Based on the ordering of the comments in the file (which are in rough chronological order), occurred around the Windows 2.0 timeframe, possibly between 2.0 and 2.03. Named after the REO Speedwagon rock band, sometimes stylized as "REO SpeedWagon".

Reunion

Windows App SDK, see Project Reunion

Roslyn

.NET Compiler Platform (also still named by its codename)

S

Saana

Lumia 650

Saimaa

Lumia 550

Salta

Surface Laptop SE

Santa Rosa

Surface Pro X (SQ2)

Santorini (JTR)

Operating system intended to run on the Surface Neo; internally codenamed after the airport of the same name

Scarlett

Xbox Series X/S

Scorpio

Xbox One X

Seattle

SQL Server 2019

Sebile

Xbox Universal Controller, scheduled to be released in 2024

Shell Update Release

Windows NT 4.0

Sherlock

Dr. Watson

Shiloh

SQL Server 2000

Sizzle

A collection of changes intended to improve overall OS/2 performance

Slate

Microsoft Management Console

Sloop

OS/2 1.2

Small Business Server "8"

Windows Server 2012 Essentials

Snowball

Windows for Workgroups 3.11

Solution Server

Windows MultiPoint Server 2010

Sparta

Windows for Workgroups 3.1

Spartan

Microsoft Edge

Sphinx

SQL Server 7.0

Spring '14, S14

Windows 8.1 Update 1

SQL16

SQL Server 2016

SQL95

SQL Server 6.0

SQLNT

SQL Server 4.21a for NT

Stimpy

Windows 95 shell and user interface

Outlook; named after the fictional cat cartoon character of the same name from The Ren & Stimpy Show

Stingray

Xbox 360 E motherboard revision (2013-2014)

Sundown

64-bit Windows NT (Win64); named as a jab at Sun Microsystems, as Solaris would be one of the main competitors in the 64-bit operating system market

Sun Valley

Windows 11

Suzuki

Surface Pocket (cancelled Surface model designed to run Andromeda OS)

Sydney

Bing Chat / Copilot

Symphony

Windows XP Media Center Edition 2005

T

Take Home

Windows Media Center internal dogfooding effort

Talisker

Windows CE 4.0

Talkman

Lumia 950

Tango

Windows Phone 7.5 July 2012 update

Tarantula

IIS for Windows 95

Tenjin

Surface Laptop SE

The Fucking Clown

Office Assistant

Thunder

Visual Basic 1.0

Titanium

Windows Mobile 6.5

Titanium

The 19H1 (first half of 2019) engineering semester of Windows as a service; the base for the Windows 10 May 2019 Update

Tonasket

Last Xbox 360 fat motherboard revision (2009-2010)

Trident

Internet Explorer 4.0 and later's layout engine

Trimaran

OS/2 1.1

Trinity

First Xbox 360 S motherboard revision (2010-2011)

Triton

Planned minor update for Neptune

Tukwila

Unofficial codename for Windows NT 4.0 coined by Dave Cutler; named after a town in the neighborhood of Seattle to poke fun at Cairo

Threshold

Windows 10; named after an in-game location from Halo: Combat Evolved. Also called Windows 8.2 in some places.

Tuva

Nano Server

U

Utopia (Home)

Microsoft Bob

V

Valo

Surface Pro 9 (5G)

Vanadium

The 19H2 (second half of 2019) engineering semester of Windows as a service; the base for the Windows 10 November 2019 Update

Vibranium

The 20H1 (first half of 2020) engineering semester of Windows as a service; the base for the Windows 10 May 2020 Update and later. Named after the fictional mineral from Marvel Comics to prevent confusion with the open source Chromium project

Vienna

Short-lived name for Blackcomb after a 2006 rename; the name was supposed to start a new set of codenames derived from popular cities and locations known for their "vistas".

Viper

Unknown early NT selfhosting effort

Vail

Windows Home Server 2011

Viridian

Hyper-V

W

Waitsburg

Final Xbox 360 S motherboard revision (2012-2013)

Whidbey

Visual Studio 2005

Whistler

Windows XP, Windows Server 2003; named after Whistler Blackcomb, a ski resort in British Columbia popular among Microsoft executives

Winball

Windows for Workgroups 3.1

Winchester

Final Xbox 360 E motherboard revision (2014-2020)

Window Manager

Windows 1.0

Windows 7

Windows 7; coined by incrementing the version number of Windows Vista (6.0) by one

Windows 8

Windows 8

Windows NT 3.99

Internal effort to advocate for smaller and more easily achievable NT releases

Windows NT 5.0

Windows 2000; not a codename per se—according to a member of the development team, "Jim Allchin didn't like codenames."

Windows Presentation Foundation/Everywhere

Silverlight

WMS 2

Windows MultiPoint Server 2011

WMS 3

Windows MultiPoint Server 2012

Wolverine

TCP/IP-32 stack for Windows for Workgroups 3.11

Wren

Outlook; originated from Bill Gates mistaking Ren, the proper codename, for Christopher Wren, the architect of St. Paul's Cathedral.

X

Xenon

Xbox 360

Hyper-V containerization system introduced in Windows Server 2016

XSP

ASP.NET (after being renamed from ASP+)

Y

Yamazaki

Windows CE 6.0

Yilan

Surface Go 4

Yukon

Xbox One (before it was renamed to Durango)

SQL Server 2005

Yushan

Surface Laptop Go 3

Z

Zaca

Surface Pro 9 (Intel)

Zamboni

Visual C++ 4.1

Zeta

Surface Duo 2

Zinc

The early 2023 engineering milestone of Windows as a service; the base for the Windows Server, version 23H2 and Azure Stack HCI, version 23H2

Zephyr

Xbox 360 Fat motherboard revision (2006-7), had A B and C versions