List of Microsoft codenames

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#	A	B	C	D	E	F	G	H	I	J	K	L	M	N	O	P	Q	R	S	T	U	V	W	X	Y	Z
== # ==
; 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)Chen, Raymond. Microspeak: FCIB, The Old New Thing. 14 November 2017.
; 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 8.1Windows Blue Vision
: 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 EssentialsGarcia, Joel. Announcing Windows Storage Server 2008 R2 Essentials, Windows Storage Server Blog. 8 November 2010.Jo Foley, Mary. There's another new Windows Server in the Microsoft pipeline, ZDNET. 2 November 2010.
; Brooklin
: Xbox Series X refresh, scheduled to be released in 2024Warren, Tom. This is Microsoft’s new disc-less Xbox Series X design with a new gyro controller, The Verge. 19 September 2023.
; Bulletproof
: Microsoft mail remote clientSmith, Chris. Some Microsoft codenames, Chris Smith's completely unique view. 30 April 2006.
== 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
; Callaway
: Windows Dev Kit 2023
; Cambria
: Surface Pro X (SQ1)
; Carina
: Surface Pro X (SQ2)
; Catapult
: Microsoft Internet Information Server
; Cascades
: Windows Essential Business Server 2008 R2, canceled successor to Windows Essential Business Server 2008. Also known as EBS "v2"
; 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 8Microsoft. Windows Embedded Standard 8 CTP3 Release Notes, Windows Embedded CTP Preview Program. 5 September 2012.
; Caspar
: Surface Pro X (Wi-Fi)
; Cedar
: Windows CE 3.0
: A codename for a component that works with both Microsoft Transaction Server (MTS) and SNA Server that converts types between host and Windows NT environments
; 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
: Always Connected PC
: 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 factorsBowden, Zac. Microsoft plans major platform upgrades for “Windows 12” that will modernize the OS with AI, faster updates, and better security, Windows Central. 28 March 2023.
; Corona
: Windows Media Player 9 SeriesJeff. A Look Back on 20 Years of The Skins Factory: Part 1, The Skins Factory. 23 February 2021.
: 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,https://twitter.com/zacbowden/status/1752328042599330121 as arsenic is infamous for its use in poisons.
; DirectX Box
: Xbox
; Doesn't Matterhorn
: Pre-reset Windows VistaCutler, David; Plummer, David. The Mind Behind Windows: David Cutler, Dave's Garage. 21 October 2023.
; 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 controllerSmith, Chris. Some Microsoft codenames, Chris Smith's completely unique view. 30 April 2006.
; 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)Smith, Chris. Some Microsoft codenames, Chris Smith's completely unique view. 30 April 2006.
; Gemstar
: WebTV for Windows
; GeorgeTown
: Surface RTHarris, Jensen. This Is The Missing Windows Startup Sound. 19 August 2022. 
; 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 4 (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
; Hartwell
: Surface Pro 10 for Business 
; 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 11Bowden, Zac. Microsoft plans major platform upgrades for “Windows 12” that will modernize the OS with AI, faster updates, and better security, Windows Central. 28 March 2023.
; Hydra
: Windows NT Server 4.0, Terminal Server Edition
: SQL Server 6.5
== I ==
; Idaho
: Unrealized successor of Windows XPSmith, Chris. Some Microsoft codenames, Chris Smith's completely unique view. 30 April 2006.
; 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
; Jalama
: Surface Pro 7
; 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 systemsThurrott, Paul. 64-bit Windows 2000 on track for mid-2000, Windows IT Pro. 27 July 1999.Windows 2000 to Launch at Comdex, 64-Bit Janus in the Wings, Findarticles.com. 26 August 1999.
; 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 OneGilbert, Ben. Microsoft accidentally sent an Xbox One to a random guy months before it was announced, Business Insider. 14 September 2016.
== 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 2XWarren, Tom. Microsoft cancels Surface Hub 2X launch, promises ‘major’ software update instead, The Verge. 3 February 2020.
; 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.
; LongARM
: Windows Vista ARMv5 porting attempts
== 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 2002De Herrera, Chris. Windows CE / Windows Mobile Versions, Pocket PC FAQ. 15 November 2009.
; 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 7.0Smith, Chris. Some Microsoft codenames, Chris Smith's completely unique view. 30 April 2006.
; 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 2Microsoft’s HoloLens 2 To Launch With A New Windows 10, Report Says
; Odyssey
: Unrealized successor of Windows 2000; project merged with Neptune in early 2000 to form Whistler.
; Omega
: Early version of Microsoft AccessSmith, Chris. Some Microsoft codenames, Chris Smith's completely unique view. 30 April 2006.
; Omega-13
: Longhorn development reset; named after the time travel device of the same name seen in Galaxy Quest's climax,Chen, Raymond. By Grabthar's Hammer, it's a Galaxy Quest documentary, The Old New Thing. 17 October 2019. 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/2http://iowa.gotthefacts.org/011607/0000/PX00194.pdf#page=52
; 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 2000Smrček, Jakub. OS Windows Mobile/Phone: strmá cesta historií (in Czech), Cnews.cz. 31 March 2011.
; 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;Chen, Raymond. Letting the boss think your project is classier than it really is, The Old New Thing. 6 May 2014. named after the fictional chihuahua cartoon character of the same name from The Ren & Stimpy Show. See Wren for alternate codename.
; 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
; Reach
: Continuum
; 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
; Selenium
: Current milestone of Windows as a Service
; 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);Porter, Mike (9 August 1998); Iowa District Court for Polk County. Plaintiff's Exhibit #6462, Comes v. Microsoft. named as a jab at Sun Microsystems, as Solaris would be one of the main competitors in the 64-bit operating system marketChen, Raymond. What was the codename for 64-bit Windows?, The Old New Thing. 5 December 2023.
; 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 95Smith, Chris. Some Microsoft codenames, Chris Smith's completely unique view. 30 April 2006.
; Tenjin
: Surface Laptop SE
; The Fucking Clown
: Office AssistantSinofsky, Steven. PM at Microsoft, Steven Sinofsky's Microsoft TechTalk. 16 December 2005.
; Thunder
: Visual Basic 1.0Smith, Chris. Some Microsoft codenames, Chris Smith's completely unique view. 30 April 2006.
; 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".https://www.cnet.com/news/microsoft-looks-beyond-vista-sees-vienna/
; Viper
: Unknown early NT selfhosting effort
; Vail
: Windows Home Server 2011
; Viridian
: Hyper-VUpdate for Windows (KB939853); MICROSOFT WINDOWS SERVER VIRTUALIZATION TECHNOLOGY CODE-NAME "VIRIDIAN"
== W ==
; Waitsburg
: Final Xbox 360 S motherboard revision (2012-2013)
; Watson
: Windows Error Reporting (not to be confused with its predecessor, Dr. Watson)
; Wayland
: Surface Laptop 4 (Intel)
; 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."Thurrott, Paul. SuperSite Flashback: NT's First Decade, Paul Thurrott's SuperSite for Windows. 8 August 2013.
; Windows Presentation Foundation/Everywhere
: Silverlight
; WMS 2
: Windows MultiPoint Server 2011
; WMS 3
: Windows MultiPoint Server 2012
; Wolfpack
: Clustering Services for Windows NT Server 4.0
; 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++ 4.1Smith, Chris. Some Microsoft codenames, Chris Smith's completely unique view. 30 April 2006.
; 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
==References==