Windows Longhorn build 4050 (idx02)

6.0.4050.idx02.030928-0552
	Build of Windows Longhorn
OS family	Windows NT
Version number	6.0
Build number	4050
Architecture	x86
Build lab	idx02
Compiled on	2003-09-28
Expiration date
Timebomb	+180 days after original install date
SKUs
	Home Edition
Product key
	TCP8W-T8PQJ-WWRRH-QH76C-99FBW
About dialog

Windows Longhorn build 4050 (idx02) is a Milestone 7 build of Windows Longhorn. On 23 January 2020, this build was listed on a thread by UX.Unleaked blog founder Grabberslasher to be released to BetaArchive's FTP server, and was released in the fifth set of his 33 Longhorn/Vista builds on 28 January 2020 as a checked/debug build alongside build 4085 (Lab07_N).^[1] It is the second and currently last publicly available Home Edition pre-reset build of Longhorn.

This build was compiled in evaluation mode and can be installed on the current date. Attempting to log onto the desktop once the timebomb has been triggered will return the user to the login screen.

New features and changes[edit | edit source]

Setup[edit | edit source]

The Setup now utilizes a brand new Slate themed background and user interface.

Upon launching the Setup, the user can now notice many drastic differences, as the previously used clock bitmap has been replaced with a countdown timer, and a Windows flag has been added to the title of each step. Simliarly, the "Final Countdown" step has been renamed to "Completing Setup".

Most Setup steps now contain a Help button, which can tell the user about what product keys do, which Upgrade option to choose, what computer names do and so on.

On the first page of Setup, Setup now mentions that the user is about to install a pre-release version of Longhorn and it will expire after 180 days.

A new "Clean install settings summary" page has been added, which enables the user to change the Installation location, Computer name, User account name, Regional settings, Keyboard layout and Time zone prior to installation. However, in this build and all subsequent builds, only the two first options are modifiable by the user.

The Drive partitioning stage of Setup now includes new options to refresh, delete, create and extend a partition.

A new Slate background that spells out the word "welcome" is now also present in the setup.exe autorun.

Windows Explorer[edit | edit source]

The Communication History prototype folder has been removed.

TCP/IP[edit | edit source]

A new TCP/IP stack has been introduced.

Bugs and quirks[edit | edit source]

Installation[edit | edit source]

When installing this build in a virtualizer, an assertion failure in the AGP440.SYS driver will occur, thus resulting in a 0x0000007E (SYSTEM_THREAD_EXCEPTION_NOT_HANDLED) bugcheck when booting into the second stage of setup. To bypass this issue, the user must set up kernel-mode debugging with WinDbg to ignore the failure^[2]. This issue does not affect real hardware or 86Box machines, as this build can install properly even on systems with an AGP slot.
When booting into the second stage of setup, the system will play a long beep on systems that have a PC speaker.
Due to this build being a PDC build like build 4051, it cannot be normally upgraded and thus can only be clean installed.

TCP/IP[edit | edit source]

The TCP/IP stack can be unstable at times.

Branding[edit | edit source]

As many branding changes did not make it into the Home Edition codebase at the time, the winver banner and Longhorn Screen Saver use the earlier Plex-themed branding.