Windows Longhorn build 4002 (Lab06 N)

Windows Longhorn build 4002 is one of the first Milestone 4 builds of the Microsoft Windows Longhorn operating system. This build makes use of the Desktop Composition Engine seen in earlier Milestone 3 builds.

Unlike later Milestone 4 builds, build 4002 uses the old i386-based setup routine instead of the newer one based on the WIM installation format. This is the first Milestone 4 build to use the new background unlike build 4001, which still uses the old M3 background.

Grabberslasher gave the details of this build on his UX.Unleaked blog. On 2020-01-23, this build was listed on a BetaArchive thread by the aforementioned user to be released to its FTP, and was released on 2020-01-31, alongside build 4040 and build 5356. WinUnleaked also had images of the build.