Windows Neptune

Windows Neptune

Microsoft Windows codename Neptune
Codename Preliminary name	Neptune, NepTune
Kernel version	NT 5.50
CPU architecture	x86
Release date	Unreleased
Support end	None
Preceded by	2000
Succeeded by	XP

Windows Neptune (internally at Microsoft also known as NepTune) was planned to become the successor of the Windows 2000 family as well as the first consumer version of Windows under the NT kernel. It was under development in 1999, until it was canceled, along with Odyssey to give way for Whistler, which would be released asWindows XP in 2001. XP included a new login screen, help center and user accounts panel originally envisioned for Neptune. However, Activity Centers were eventually dropped. As stated in confidential Microsoft documents, Neptune was to be released in Q4 of 2000, planned to have 64-bit edition (referred to as "NT64") for the upcoming Intel Itanium processor, "Solar Coaster" (Unix Services for NT), Internet Explorer 6 (which was also in development at the time) and some Anti-Piracy features. There is evidence that five service packs were planned for Neptune.

A successor called Windows codename Triton was mistaken as a service pack, but as shown in Antitrust documents, it was actually a successor to Neptune which would bring minor updates and enhancements.

Other Neptune SKUs

Microsoft Anti-trust documents from Neptune era indicate that Neptune was to have not only one, but several editions, namely "Entry-Level", "Standard" and "High-End", which could translate into these modern SKUs: "Starter", "Home" and "Professional / Server". It is unknown what these editions would actually become, if Neptune was ever released.

There are also several strings in file USETUP.EXE from Neptune build 5111.1 that clearly mention "Neptune Server". These references could be leftovers from Windows 2000, if all "2000" strings were simply replaced with "Neptune" during the rebranding process.

Timeline

NOTE: some of the information provided in this timeline is based only on rumours or unconfirmed build numbers. Therefore, this timeline can not be taken as a reliable source of information.

• Around 13-07-1999: Neptune build 5.50.5022.1 is compiled
• Around 20-09-1999: Neptune build 5.50.5067.1 is compiled
• Around 8-11-1999: Neptune build 5.50.5095.1 is compiled
• Around 17-11-1999: Neptune build 5.50.5099.1 is compiled
• Early December 1999: Microsoft announced the details of Windows Neptune to a few testers
• December 10, 1999: Neptune build 5.50.5111.1 is compiled
• December 27, 1999: Neptune build 5.50.5111.1 is sent to a few testers
• Early January 2000: Neptune builds 5.50.5116.1 and 5.50.5117.1 are compiled
• January 21, 2000: Paul Thurrott reveals that both Neptune and Odyssey are cancelled and will be replaced by Whister.
• March 20, 2000: Windows Whistler build 2211.main.000309-1512 leaks, it looks like Windows Neptune but it isn't.

Builds

• No information available
• Existence doubtful
• Information or pictures available
• Leaked or released

• Neptune Build 5.50.5000
• Neptune Build 5.50.5022.1
• Neptune Build 5.50.5067.1
• Neptune Build 5.50.5095.1
• Neptune Build 5.50.5099.1
• Neptune Build 5.50.5111.1 - Neptune Developer Release and M2 build
• Neptune Build 5.50.5116.1
• Neptune Build 5.50.5117.1
• Neptune Build 5.50.5118
• Neptune Build 5.50.5119
• Neptune Build 5.50.5120
• Neptune Build 5.50.5179.1