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Windows Longhorn

From BetaArchive Wiki
For post-reset history and builds, see Windows Vista.
Windows Longhorn Logo.png
Windows "Longhorn"
Preliminary name
Kernel version NT 6.0
CPU architecture x86, x64, IA-64
Release date N/A
Support end N/A
Preceded by Windows XP
Succeeded by Windows Vista

Longhorn was the codename for the planned successor of Windows XP.

One of the original - and largest - changes is that, with "Longhorn", the .NET Framework would be integrated into the core Windows platform, deprecating the traditional Win32 API. During development, portions of the operating system were rewritten, causing memory leaks and instability, particularly in Windows Explorer.

Development was reset, but post-reset builds continued to use the "Longhorn" codename until the final name, Windows Vista, was announced on 22 July 2005.



"Longhorn" was chosen as the codename for the operating system to represent its initial status as an internim release between Windows XP (codenamed "Whistler") and "Blackcomb". Whistler and Blackcomb are names of mountains in British Columbia, Canada,[1][2] and Longhorn is the name of a saloon located in between the two mountains, representing the operating system's initial status as an internim release between the two products.[3] Bill Gates would later state that this choice for a codename of the operating system was "a bit random".[4]


The popular belief is that pre-reset "Longhorn" builds are based on Windows XP. This was likely spurred by Paul Thurrott's statement on his review of build 5048: "The problem, I was told recently, was that the underpinnings of Longhorn--then based on the Windows XP code base--were struggling under the weight of all of the technologies that Microsoft planed to implement in this release."[5] However, pre-reset "Longhorn" builds are based, not on XP, but on Windows Server 2003 release candidate code. The xpclient release branch, dedicated to XP, spun off from the main branch in 2001. The main branch continued to compile Server 2003 builds at the 3xxx range, such as build 3663 (release candidate 1), until the dnsrv branch dedicated to Server 2003 spun off from the main branch in 2002. After that, the main branch began compiling Longhorn builds.[6]


Build 3683

  1. First build to include Desktop Composition Engine (basic window transparency effects).
  2. First build to include Sidebar.
  3. A new theme, Plex, was introduced.
  4. Internet Explorer was updated to version 6.05.
  5. A new display settings applet was introduced, based on the Windows Presentation Foundation.

Build 3706

  1. New wallpaper.
  2. Updated a bit Plex.
  3. Animated files and folders icon in the Explorer.
  4. Introduced application MyTVApp.

Build 3713

  1. Sidebar is enabled by default.
  2. The only build to contain both Media Center and Tablet PC editions.

Build 3718

  1. Removed Classic View from Control Panel.

Build 4001

  1. New Setup UI and OOBE.
  2. Using install.wim during the installation.

Build 4002

  1. Updated wallpaper.

Build 4005

  1. New Setup UI.
  2. Updated Wallpaper and Screen saver.

Build 4008

  1. Some improvements in Internet Explorer.
  2. Updated Plex theme.
  3. Parental Controls introduced.

Build 4011

  1. New bootscreen.

Build 4015

  1. New wallpaper and logon screen.
  2. Windows Messenger was updated to version 5.0.

Build 4017

  1. Introduces a working DCE.

Build 4020

  1. Skipped OOBE and changed watermark to "Longhorn Professional".

Build 4028

  1. Ctrl+Alt+Delete now opens a security interface instead of Task Manager.

Build 4029

  1. Some changes in the Setup UI and Plex theme.
  2. Wallpaper and logon screen were updated.
  3. Outlook Express updated.
  4. Introducing the Game Library.
  5. Introducing the Sync Manager.

Build 4030

  1. The first build that had Home Edition SKU.

Build 4031

  1. Bugfixes from earlier builds.

Build 4032

  1. New wallpaper.
  2. File a Longhorn bug added.
  3. My Computer icon is updated.

Build 4033

  1. Some improvements in the Internet Explorer.
  2. The first build that had ia-64 version.

Build 4038

  1. Introduced Aero Theme.

Build 4039

  1. Changes in the Setup UI.
  2. Some updates in the Explorer.

Build 4040

  1. Uses an older code.
  2. A bit changed Setup UI.

Build 4042

  1. Plex theme is replaced by Slate (only lab06_n compile).
  2. New logon screen, wallpaper and boot screen.
  3. New Task Scheduler.
  4. "Start" is removed from the Start Menu button (when sidebar is enabled) and "My" in the Start menu is removed everywhere.

Build 4048

  1. New Setup UI, screen saver and logon screen.

Build 4050

  1. Windows Media Player 9 is updated.
  2. The first build that had a checked version.

Build 4051

  1. The first build that had 64-bit version.

Build 4053

  1. Patched some network bugs.

Build 4066

  1. Added Jade Theme.
  2. Updated icons in the Start Menu.
  3. Introduces DWM and Aero.

Build 4074

  1. The first build that included full DWM and Aero. However, it requires some work in order to enable it.
  2. The only build that had Animated Preview Pane Aurora. Requires patching to show up in Explorer.

Build 4081

  1. Removed many core features.
  2. Starting this build introduces many bugs, ex. BSOD on Safe Mode.
  3. A bit updated Setup UI.

Build 4083

  1. New wallpaper tree, reverted some icons with XP ones.
  2. Removed few Sidebar features.

Build 4087

  1. New setup text.

Build 4088

  1. Reverted some core features.
  2. Fixed WordPad.

Build 4093

  1. The last Longhorn build before reset.
  2. Fixed Windows Classic theme.
  3. Early version of UAC called Windows Security.
  4. Early version of Movie Maker 3.0.
  5. New Avalon-based Power Options panel.
  6. New Text To Speech panel.
  7. Last build that does not need ACPI to work since it uses NTLDR.


Several different logos were created throughout the development of "Longhorn". Early builds used 2D and 3D representations of a longhorn bull; later builds included white or glass versions of the Windows flag.

Concepts, presentations, demos and prototypes

Implementation of concepts

Twitter user Lucas Brooks (mswin_bat) found that porting the private Milestone 7 Aero theme to a Milestone 5 build like 4017 enables the striped sidebar shown in a demo.[8]


For server builds, see the Windows Server 2008 page.
  • No information available
  • Existence doubtful
  • Information or pictures available
  • Leaked or released

Lab guide (Source: Grabberslasher)[9]

  • Lab01: Base (Kernel)
  • Lab02: Networking
  • Lab03: Server
  • Lab04: Management
  • [Lab05:] Main
  • Lab06: Desktop
  • Lab07: IIS/COM+

Milestone 2

Milestone 3

Milestone 4

Milestone 5

Milestone 6

Milestone 7

Milestone 8

Development reset

See Windows Vista.

See also


See also

BetaArchive forum

External links


Paul Thurrott

Other non-Microsoft