Windows Vista build 5001

Windows Vista build 5001 is among one of the first builds of Windows Vista to be compiled after the development reset of Windows "Longhorn". Images of this build were released by UX.Unleaked on 1 May 2008. On 23 January 2020, Grabberslasher, the owner of the website, announced that this build would be released to BetaArchive. It was later released in the third set of his 33 Longhorn/Vista builds on 26 January 2020, alongside build 4048 and multiple compiles of build 5000.

This is the last client build that does not require ACPI to work since it uses. Later post-reset builds require ACPI to operate since they use  instead. It is also the final build to support being installed to a user-defined folder instead of, as well as the last available client build of Windows (excluding Service Pack 3 builds of Windows XP) to use i386 installation process and it was eventually replaced with WIM installation process since build 5048.

It is the last build to support an upgrade from Windows NT 4.0, Windows 98, Windows 98 SE and Windows Me.

Setup
Similar to previous compiles of post-reset Vista builds, the setup re-uses the i386 installation process found in Windows XP and Windows Server 2003.

Default wallpaper
This build has a new default wallpaper, which is simply a humorous edit of Bliss with an image of a Texas Longhorn bull placed at the center, in reference to the project's codename.

Windows Media Player 10
Windows Media Player has been updated from 9 Series to 10. Because of this, the Control Panel now includes an option called Portable Media Devices, and the User-Mode Driver Framework that comes with it is present as well.

Upgrade
The boot menu will refer to setup as "Microsoft Windows XP 64-Bit Edition Version 2003 Setup" when performing an upgrade, despite being an x86 build.

Installation media error
It is possible to get an endless loop of error messages asking the user to insert the currently inserted disc, even if the user has the correct media inserted.

OOBE

 * The animated "Question Mark" assistant in the Out of Box Experience (OOBE) does not appear until reaching the second page.
 * The OOBE crashes when loading the desktop on first boot.

Windows Explorer

 * The details pane in Windows Explorer is broken, while the panes and tasks that do work cannot be opened or closed. In Control Panel, they also quickly disappear after loading. As such, the Classic view in Control Panel is almost impossible to access unless the user refreshes the page and quickly clicks on the option. This issue can be resolved by disabling the "Fade or slide menus into view" option in the Performance Options.
 * Right-clicking on any file in Explorer can cause DEP to block Explorer from executing data as code, however this does not always occur. Explorer immediately crashes and is automatically restarted after the user clicks OK on the DEP message box.

Visual styles
There is a small bug with theme previewing, where the window borders may appear smaller than they actually are.