Windows Longhorn

"Longhorn" was the planned successor of Windows XP. This project never released, but rather its development was reset, being the new project Longhorn/Omega-13. The earliest builds after the reset were known as "Codename Longhorn", causing some confusion.

Builds
Confirmed, Unconfirmed , Fake

Development Reset

 * After the compilation of build 4093, the development of Longhorn was reset, mainly because of the instability of the current Longhorn branch. At about 9PM, on the same day as the compilation of 4093, Microsoft stopped development of Windows Longhorn, and started fresh using Windows Server 2003 R2 as a codebase. Development of Longhorn continued, albeit many features originally slated for Longhorn were delayed or dropped to provide a more realistic operating system.
 * See Windows Vista  for more information.