Windows Longhorn/6.0.3663.Lab06 N.020728-1728

Windows "Longhorn" build 3663 (with a build tag of 3663.Lab06_N.020728-1728) is an unconfirmed early Milestone 2 build of Windows Longhorn, and its earliest known build.

Microsoft originally started the development of Longhorn based on the Server 2003 codebase (known as .NET Server at the time), specifically based on  the official release candidate 1 build. It would make sense that the first build to be compiled would have the same build number, but there is evidence that proves that Longhorn builds were being compiled as early as 2001.

Note that Longhorn must be compared to Windows XP and not to Server 2003 as Longhorn was intended to be a client release of Windows.

History
The first known screenshots were posted by Calvin Zhang in October 2002. The screenshots were later made popular by the beta group xBetas known for leaking other Windows builds such as 3683, which used Calvin's screenshots and watermarked them.

It has been rumored that this build was leaked in the past, but there is no evidence to support this claim.

A few more screenshots (including the wallpaper) have surfaced on the internet as early as 2007, but their source remains unconfirmed and it is debated that they are fake. However, it is not possible to verify that because too little is known about early Longhorn builds.

A fake video of this build surfaced on YouTube on February 18, 2021.

Features and Changes
The following changes are observed compared to Windows XP Service Pack 1 leaked beta build 1081:

Kernel

 * The kernel has already been bumped to version 6.0, which is unusual for early builds of a Windows version.

Desktop

 * The default Bliss Wallpaper from Windows XP has been changed to bales of hay, and the text "Longhorn alpha" has been added unlike the leaked build 3683 (which says "M3 build", and the banner has a yellow tint, unlike the white banner seen here).
 * The Windows Logo seen on the start button has been changed to all-white instead of the default colored one. This also appears in later builds, up until post-reset build 5600 of Windows Server 2008.
 * All screenshots of this build appear to use the Silver variation of the Luna theme. It is claimed that this is early Plex, but there is no evidence to support this.

Login Screen

 * The login screen is changed to a gray one identical to later Milestone 3 and early Milestone 4 builds. It also includes the time and date, and seems to support Chinese dates as well without problems.

System Properties

 * This build already calls itself "Microsoft Windows Longhorn" in System Properties, even though the watermark still says "Microsoft Windows XP".
 * This build says "Version 200X" unlike later builds which say 2003 or 2004.

Windows Explorer

 * The "Up" button appears to be removed by default from the Standard Buttons toolbar.
 * This build introduces disk space indicators for all drives (including CD/DVD drives).
 * Automatic icon sizing seems to be already implemented in this build.
 * Drive letters and folders appear to be underlined in the screenshot by Calvin Zhang, which is odd and not seen in other Windows versions. The fonts are different as well. In addition, the free space is displayed in megabytes, whereas later builds display it in kilobytes.
 * The unconfirmed screenshot shows that this build already has the new tasks pane seen in 3683 and later, as well as the Find feature. However, the screenshot by Calvin Zhang lacks this feature. It could be possible that the GUID for the Shell View provider was removed from the registry, which reverts later Milestone 3 and early Milestone 4 builds to a classic Windows XP tasks pane.

Autorun

 * The autorun has already been changed to brown seen in later builds. The text has been made bold and black as well. The title text has been changed to "Welcome to Microsoft? Codename Longhorn". The question mark is likely a bug, and the intended character is the registered sign ®.
 * The logo is changed from the default Windows one to an early Longhorn logo.