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.

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.

Changes
Despite being similar to Windows XP due to it being compiled early on in its development, this build still has a not entirely insignificant number of changes due to the busy nature of Microsoft around the reset and the fact that almost a month separates this and build 5000.

Default wallpaper and branding changes
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. Alongside this, the  banner is the one from build 5000, which has been updated to say "lh" (short for Longhorn) in place of "XP". These hastily made rebrands raised doubts about the authenticity of the build prior to it being made publicly available, as well as several forum threads that have since failed to prove the fact that the images published by the person who originally shared the build were falsified.

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.

Minor changes
The background of the User Accounts control panel option has been changed from blue to gray. Gray is used as the overall color in Windows Server 2003.

Longhorn Help Place
In builds 5000 and 5001, a "Longhorn Help Place" button has been added to the Help and Support Center. When invoked, HelpCtr will attempt to launch, which does not exist in this build but does exist in some Longhorn pre-reset M6 builds, such as 4033. It will appear to do nothing as none of the files required to launch  exist in this build.

Bugs
This build does not have an entirely insignificant number of bugs, likely due to the significant changes being made under the hood to the operating system around this time (the first 5000 build was compiled almost two months before this build):
 * The boot menu will refer to setup as  when performing an upgrade, despite being an x86 build.
 * 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.
 * 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.
 * There is a small bug with theme previewing, where the window borders may appear smaller than they actually are.
 * 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.
 * 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.