Windows Longhorn build 4040

Build of Windows Longhorn
OS familyWindows NT
Version number6.0
Build number4040
Build labLab04_N
Compiled on2003-08-28
Expiration date
Timebomb2004-02-24 (+180 days)
Product key
About dialog

Windows Longhorn build 4040 is a Milestone 6 build of Windows Longhorn and is one of the last builds for that milestone. Grabberslasher first gave the details of this build on his UX.Unleaked blog. On 23 January 2020, this build was listed on a BetaArchive thread by the aforementioned user to be released to its FTP, and was released on 31 January 2020, alongside build 4002 and build 5356. This build is one of the last builds to include the Plex theme, together with the main compile of 4042.

Overall, this build has a very similar feature set to builds 4038 and 4039.

Setup[edit | edit source]

Although setup altogether is mostly similar to previous builds of Longhorn, the numeral and clock sprites now no longer contain a transparent background.

Features[edit | edit source]

  • Much of the interface remains similar to that of build 4038 due to Lab04's use of older code, likely from the main lab builds. This can be seen in areas such as File Explorer, where the back, forward, favorite and My Computer icons are identical to build 4038.
  • Related to Lab04's use of older code, the service winux does not exist, which means theming cannot be easily enabled/disabled.

Bugs and quirks[edit | edit source]

Installation[edit | edit source]

Some copies of this build's installation media cannot be booted normally due to a call to a non-existent index in the INSTALL.WIM by SETUPLDR.BIN. To install this build in this case, use a WinPE from a previous build.

Safe mode[edit | edit source]

Trying to log in after booting into safe mode results in an error due to the User Profiles Service and Group Policy Service being disabled.

The services can be manually enabled in safe mode by adding the following entries to the service whitelists in the registry:





Gallery[edit | edit source]

UX.Unleaked images[edit | edit source]