Windows Longhorn/6.0.4015.Lab06 n.030403-1706

Windows "Longhorn" build 4015 (with a build tag of 4015.Lab06_n.030403-1706) is one of the first Milestone 5 builds of the Microsoft Windows "Longhorn" operating system. It was the first Windows Longhorn build to be publicly showed by Microsoft, during WinHEC 2003 (May 6-8, 2003).

At the conference, potentiality of the new "Desktop Composition Engine" (DCE) was demonstrated: with the help of some scripts included in batch files, several animated effects applied on all Windows shell items were showed, and the dynamic window scaling feature according to screen density was examinated.

Unlike 4015.main.030328-1500, this build has yet to leak; however, xBetas has released an additional screenshot of this build.