List of Microsoft codenames

#

 * 6 on 6 (Windows Mobile 6.1.4)

A

 * ADOS (OS/2 1.0)
 * Advanced Windows (Windows NT 3.1)
 * The original announced name for NT-based Windows, see Razzle
 * Alder (Windows CE 1.0)
 * Anaconda (Xbox Series X/S)
 * Andromeda
 * Canceled phone variant of Windows Core OS
 * Another Fucking Driver (Ancilliary Function Driver; )
 * Application Framework Extensions, AFX (Microsoft Foundation Class Library)
 * Apollo (Windows Phone 8)
 * Asteroid (Windows 2000 Service Pack 1)
 * Astro (MS-DOS 6)
 * Avalon (Windows Presentation Foundation)

B

 * 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)
 * Blue (Windows 8.1)
 * Bobcat (Windows Small Business Server 2003)

C

 * Cairo
 * Canceled successor of Windows NT 3.x that aimed to implement Bill Gates's "Information at your fingertips" vision
 * Cairo Domains (Active Directory)
 * Cairo Messaging (Microsoft Exchange)
 * CairOLE (OLE 3.0)
 * Cascades
 * Canceled successor to Windows Essential Business Server 2008 based on Windows Server 2008 R2.
 * Cascadia (Windows Terminal)
 * Cashmere (Word for Windows)
 * Cedar (Windows CE 3.0)
 * Centro (Windows Essential Business Server 2008)
 * Chelan (Windows Embedded Compact 7)
 * Cherry Hill
 * Windows 11 shell experience pack updated via the Store
 * Chicago (Windows 95)
 * Cleveland
 * Alternative name for a canceled successor of Windows 95, more commonly known as Nashville
 * Cobalt (WaaS 21H2 development semester; Windows 11)
 * Colorado (Windows Small Business Server 2011)
 * Control Program/DOS, CP/DOS (OS/2 1.0)
 * Follows IBM mainframe product naming
 * Copper (WaaS 23H2 development semester)
 * Cougar (VMM32)
 * Cougar (Windows Small Business Server 2008)
 * Crossbow (Windows Mobile 6.0)
 * Cutter (OS/2 1.3)

D

 * Darwin (Windows Installer
 * Daytona (Windows NT 3.5)
 * Detroit (USB supplement update for Windows 95 OSR2)
 * DirectX Box (Xbox)
 * DOS 5 (OS/2 1.0)
 * Name used primarily by Microsoft; implies that OS/2 is the successor to the multitasking MS-DOS 4 (not the widely available MS-DOS 4).
 * Durango (Xbox One)

E

 * Edmonton (Xbox One S)
 * eHome (Windows Media Center)
 * Eiger (Windows Fundamentals for Legacy PCs)
 * Emerald (Windows XP Media Center Edition 2005 Update Rollup 2)

F

 * Fastbike
 * Fast boot in Windows Neptune (Profile Accelerated Boot Accelerator)
 * Freestyle (Windows XP Media Center Edition)
 * Frosting (Microsoft Plus! for Windows 95)
 * Fire Steel
 * Internal Windows 11 self-hosting effort
 * Firebird
 * An upcoming update for Windows 10 Team.
 * Fusion (WinSxS)
 * Fusion (.NET Framework CLR Loader)

G

 * Galileo (Windows CE 3.0)
 * Game SDK (DirectX)
 * GeorgeTown (Surface RT)
 * GeorgeTown X (Surface Pro)

H

 * Haiku (Modular Windows)
 * Harmony (Windows XP Media Center Edition 2004
 * Hydra (Windows NT Server 4.0, Terminal Server Edition)

I

 * Idaho
 * Unrealized successor of Windows XP
 * Immersive Launcher, Immersive Shell (Start screen)
 * Impala (Windows NT Embedded 4.0)
 * Indigo (Windows Communication Foundation
 * Interface Manager (Windows 1.0)
 * Iron (WaaS 21H1 development semester; Windows Server 2022)

J

 * Jaguar
 * The MS-DOS subsystem in Windows 95. A standalone retail release was also planned at one point, which ultimately ended up not materializing
 * Jameson (Windows CE 4.1)
 * Janus (Windows & MS-DOS 5)
 * Combined bundle of Windows 3.1 and MS-DOS 5
 * Jastro (Windows & MS-DOS 6)
 * Combined bundle of Windows 3.1 and MS-DOS 6; portmanteau of Janus and Astro
 * Jupiter (Windows CE 2.0)
 * Jupiter (Windows Runtime)

L

 * Lite (Windows 10X)
 * Lockhart (Xbox Series X/S)
 * Lonestar (Windows XP Tablet PC Edition 2005)
 * Longhorn (Windows Vista)
 * Named after a bar situated between the Whistler and Blackcomb mountains.

M

 * Macallan (Windows CE 5.0)
 * Magneto (Windows Mobile 5.0)
 * Manganese (WaaS 20H2 development semester)
 * 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 (Windows 10X)
 * MoGo (Start screen)
 * Monad (Windows PowerShell)
 * Monarch (Outlook PWA)

N

 * Nashville (Internet Explorer 4)
 * Originally referred to a canceled successor of Windows 95.
 * Neptune, NepTune
 * Canceled NT-based successor of the Windows 9x series; project merged with Odyssey in early 2000 to form Whistler.
 * Nickel (WaaS 22H2 development semester; Windows 11 2022 Update)
 * NoDo (Windows Phone 7 March 2011 update)
 * NT OS/2, NTOS
 * NT-based rewrite of OS/2 canceled in favor of Windows NT, see Razzle
 * NT Windows (Windows NT)
 * Alternative name for Windows NT before that name was standardized, see Razzle

O

 * O'Hare (Internet Explorer 1)
 * Named after the international airport near Chicago, the codename for Windows 95.
 * Odyssey
 * Unrealized successor of Windows 2000; project merged with Neptune in early 2000 to form Whistler.
 * One Outlook (Outlook PWA)
 * Opus (Word for Windows)
 * 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
 * Panther (WIM-based Windows setup)
 * Pegasus (Windows CE 1.0)
 * Photon (Windows Phone 7)
 * Polaris
 * Canceled desktop variant of Windows Core OS
 * Portable OS/2
 * NT-based rewrite of OS/2, see Razzle
 * Porthole (Windows Libraries for OS/2)
 * Portico (Windows Phone 8 GDR1)
 * Protogon (ReFS)

Q

 * Quatro (Windows Home Server)
 * Quebec (Windows Embedded Standard 7)

R

 * 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)
 * Redstone (Windows 10 Anniversary Update through October 2018 Update)
 * Named after an ingame resource from Minecraft.

S

 * Santorini (Windows 10X)
 * Scarlett (Xbox Series X/S)
 * Scorpio (Xbox One S)
 * Shell Update Release (Windows NT 4.0)
 * Sherlock (Dr. Watson)
 * Sloop (OS/2 1.2)
 * Snowball (Windows for Workgroups 3.11)
 * Solution Server (Windows MultiPoint Server 2010)
 * Sparta (Windows for Workgroups 3.1)
 * Spartan (Microsoft Edge)
 * Spring '14, S14 (Windows 8.1 Update 1)
 * Stimpy (Windows 95 shell and user interface)
 * Stimpy (Outlook)
 * Sun Valley (Windows 11)
 * Symphony (Windows XP Media Center Edition 2005)

T

 * Take Home
 * Windows Media Center internal dogfooding effort
 * Talisker (Windows CE 4.0)
 * Tango (Windows Phone 7.5 July 2012 update)
 * The Fucking Clown (Office Assistant)
 * Titanium (Windows Mobile 6.5)
 * Titanium (WaaS 19H1 development semester; Windows 10 May 2019 Update)
 * First Windows release under the Azure semester scheme
 * Trimaran (OS/2 1.1)
 * Triton
 * Planned minor update for Neptune
 * Tukwila
 * Internal effort to advocate for smaller and more easily achievable NT releases
 * Threshold (Windows 10)
 * Named after a location seen in Halo: Combat Evolved.

V

 * Vanadium (WaaS 19H2 development semester; Windows 10 November 2019 Update)
 * Vibranium (WaaS 20H1 development semester; Windows 10 May 2020 Update and later)
 * Named after the fictional mineral from Marvel Comics to prevent confusion with the 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".
 * Vail (Windows Home Server 2011)

W

 * 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)
 * Window Manager (Windows 1.0)
 * Windows 7
 * Originated by incrementing the version number of Windows Vista (6.0) by one
 * 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)
 * 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)

Y

 * Yamazaki (Windows CE 6.0)