Windows Longhorn build 4005

Windows Longhorn build 4005 is a Milestone 4 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 second set of his 33 Longhorn/Vista builds on 25 January 2020, alongside build 4039 (Lab06 n.030824-1954) and the Home Edition of build 3790.1232.

It is a major update from previous builds such as build 4001, including an updated .WIM installation. It uses the new branding in "winver" but still retains the Windows XP boot screen.

It is also the last build to use centered title bars, which were later reintroduced in Windows 8. On maximized windows, however, centered title bars remain until build 4020.

Setup
Similarly to 4001, the Setup interface has been heavily updated. Now being able to partition a drive correctly and having an entirely new look, setup is now less basic than build 4001. It also uses the WinPE once again, rather than using the older i386 installation method, and therefore utilizes an  once again, unlike build 4002.

When inserting a product key, unlike 4001, the letters are no longer capitalized, however they aren't spaced in between with dashes every 5 letters. The End-of-User License no longer also requires you to scroll all the way down in order to agree to it. Instead, the text box containing all of the information about the EULA can still be scrolled through, however the options have been separated. Drive partitioning has been improved, now including each disk with all of its respectful partitions, rather than just the partitions only. Copying files also includes more description over what is going on exactly.

Once restarting and reaching the Out of Box Experience, you will be greeted by a very bland screen, which asks you to. This is where setup detects hardware and finalizes the install. Eventually, you will be finally greeted with a similar interface found in 4001, where you create a user account and then eventually log into Windows. A new wallpaper has been added, similar to the one used for the rest of setup. However, upon creating a new account, OOBE will crash and you'll be sent straight to the desktop with the administrator account only.

New features

 * Nearly all references to Windows XP have been removed by this point, most notably the logo shown within the About Windows dialog box, which was replaced by the Longhorn logo, showing the copyright date, 2006 (assumably a typo of 2003). Windows XP is still referenced in the boot/safe to shutdown screen, in the Help & Support Center, and in the Windows XP Tour.
 * Tiles have been modified slightly, such as the slide show tile having a smaller slideshow and the search the internet tile being a button only rather than including a search box alongside it.

Installation

 * Setup will take longer to boot from the installation media when the computer is set to SATA mode.
 * USB Devices may not work during setup when the computer is set to SATA mode.
 * On some machines that use IDE emulation, setup will hang when reading from the installation media.
 * Unpartitioned drives cannot be selected for installation in the setup. To setup from a hard drive without any partitions, select the disk that Windows will be installed on. Otherwise, you can partition and format a drive outside of this build's setup.
 * Many drivers aren't installed by default during the hardware portion of setup and have to be installed manually.
 * OOBE will crash upon creating a user account. Although you will still be able to use Windows, you will only be able to use the administrator account.

Desktop Composition Engine
Desktop Composition Engine requires either compatible hardware or VMware Workstation 6.5.x to work (just 6.5x compatibility won't work), otherwise it will result in a black screen that can only be exited by a hard reset.

Control Panel

 * Display Properties mentions the Luna theme as the Plex theme.