Draft:LogonUI

LogonUI, officially called Windows Logon UI, is a user interface that was intended to provide an easier and more friendly login experience. It contains most of the functionality of its earlier login prompt, with a revamped and more user-friendly UI. It also handles the Windows Security menu (invoked when pressing Ctrl) starting with Windows Vista.

Predecessors
Before the new LogonUI was introduced, both Windows NT and Windows 9x used a login prompt, which was basic in terms of design and functionality. The Windows 9x family also contains a "Family Logon" interface, which was still a prompt but with a different design to provide a more friendly logon experience.

Neptune and Whistler
LogonUI was first introduced in Windows Neptune build 5111, however in Neptune and early builds of Windows XP, it was HTML-based (stored in ) and therefore relies on Internet Explorer technologies. As it was ported to Windows XP build 2223, the Windows logo at the top was changed to four orbs which were colored after the Windows logo, with every one showing a part of it. Starting with at least build 2225, it became DirectUI-based, and therefore does not require Internet Explorer to be functional. The UI also has been given a major overhaul.

A variation of the final design was introduced in build 2428, which would be finalized in build 2465. Builds 2474 and 2475 though have an animated Windows XP logo on the login screen, which would be reverted again in build 2481.

Pre-reset
In early builds (3683 - 4011), LogonUI features a live clock at the top right corner and a different color scheme to fit with the newly introduced Plex theme.

More significant updates to LogonUI were introduced in later builds of Longhorn: Build 4015 removed the live clock (this feature would return in Windows 8) and now consists of a box with the Windows logo above it and a milestone-appropriate background. With build 4029 (main), the Windows logo became transparent and now also slides from the top. The box now only appears when the user is prompted to log in. It also now handles the Windows Security menu, replacing Task Manager. To fit into the new design language of Milestone 7, the transparent Windows logo was replaced with the colored one from Windows XP. Also, the wallpaper changed to a skinny blue gradient, then in build 4048 to a solid black background. This design persisted up to the last pre-reset build.

Post-reset
The development reset caused LogonUI to be reverted to the design seen in Windows XP. It was even temporarily disabled in Windows Vista build 5048, which caused the legacy login prompt to be used by default. After it was reactivated in later builds, significant changes were made to LogonUI, as it now again handles the Windows Security options.

Starting with Windows Vista build 5308.6, LogonUI got a major overhaul, making having multiple users easier, as it can fit much more users in the login screen.

As a side effect when making LogonUI handle the Windows Security menu, if the LogonUI executable is missing, an error will pop up, making LogonUI mandatory starting with Vista.

Windows 8 and 8.1
Starting with Windows 8 build 7875, LogonUI got a major overhaul, making user profiles bigger for use on tablets, adding a lock screen to show the date and time while logged off, and making it fit with the Metro UI of Windows 8 and 8.1. However, it is still mostly DirectUI-based and can be run without DWM. Do note that the swiping animation of the lock screen and the power menu will be broken as it uses DWM to render.

Windows 10 and later
Since Windows 10 build 9888, by changing a registry value, a hidden LogonUI can be enabled, which has a new design that fits with the new design language of Windows 10. This also marks the debut of the UWP-based LogonUI, as its functionalities and resources are now separated to multiple  DLL files. This allows LogonUI to be updated more frequently in newer versions.

Although most functionalities and resources are now separated from the main executable, it still handles basic logging on and off functionalities and a command-line version of LogonUI, which is used for Windows Server Core, where  DLL files do not exist. It can also be enabled on client versions and Windows Server with Desktop Experience by the method below.

Trivia

 * Although there is no interface to turn off the new Welcome screen right on the new login screen, in Windows XP the old login prompt can be brought back by pressing Ctrl three times. The new login screen cannot be brought back again after pressing the key press without having to log off again.
 * The registry value to configure LogonUI was located in, under the string value  . By default, it is set to  , but it can be changed to other executables or left blank to bring back the old login prompt.
 * Windows 10 and newer include a command-line version of LogonUI, which is used in Windows Server Core by default starting with Windows Server 2016, replacing the regular LogonUI. It can also be enabled in Windows 10, 11 and Windows Server with Desktop Experience by using the following methods:
 * creating a value called  in   and set it to 1
 * renaming  in
 * In the command-line version of LogonUI, when in client versions of Windows, the message to press Ctrl can be shown even though it is not enabled, and pressing any key will bypass it.
 * In the command-line version of LogonUI, if not using the Server Core version, after logging in and locking Windows by pressing Win, right clicking the command-line window, going to properties and pressing "Learn more about legacy console" will open up a web browser even though the system is locked.
 * LogonUI was not present in the Windows Server line until Windows Server 2008 build 5112. Windows Server 2003 continued to use the classic login prompt from Windows 2000 instead, which was completely phased out in the aforementioned build.