Windows Longhorn build 3663

Windows "Longhorn" build 3663 is the earliest known build of Windows Longhorn for which screenshots exist, and possibly the first build based on the Windows Server 2003 Release Candidate 1 codebase. A rumor exists that the build was leaked in the far past, but due to the low interest, the download links were permanently removed.

Visual changes in the build include replacement of the colored Windows flag on the start button with a single white color variant. Also, the silver luna theme is used by deafult. It also seems to have the login screen from build 3683 and disk space indicators in Explorer. Otherwise, this build is not much different from Windows XP or Server 2003, which is one of the few references to windows longhorn (along with the wallpaper).

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