Windows Longhorn build 4020

Windows Longhorn build 4020 is a Milestone 5 build of Windows Longhorn. A screenshot of the build was shared on the BetaArchive Discord server on 27 November 2018. On 3 December 2018 this build was uploaded to the BetaArchive FTP server, along with build 4032.

Unlike other Longhorn builds, it was compiled in evaluation mode, and can be installed on the current date. Once the timebomb is triggered, Windows still functions, but a Windows Product Activation error message will show up that this build must be activated. Additionally, the timebomb is extended to 445 days, being one of the "Longhorn" builds that has the longest timebomb.

This build is mislabeled with a buildtag of "6.0.4020.idx02.030430-2218" in certain aspects of this build.

Setup
Although setup mostly resembles that found in the previous build, Setup now features a new page that includes options for initiating an upgrade or a clean installation. The minimum required version required to perform an upgrade installation is build 4000.

New features and changes
This build is very similar to build 4015 (main) and build 4017, however there are some minor changes:


 * Notably, the notifications appearance has been updated, which features a more sleeker design and the notification icon on the side now shows a reflection and bouncing up and down when hovered.
 * The Windows Explorer has been updated to no longer leak memory when the Windows Sidebar is enabled. WinFS also works in this build, just like in 4015.
 * The OOBE is now completely skipped; after the hardware portion of setup, the system logs on to the Administrator account. This was later returned in Windows Vista build 5259.
 * This build changes the "Longhorn XP" references to simply "Longhorn", such as in the desktop watermark. In build 4029 (main), it was renamed into onghornLay rofessionalPay (into Pig Latin strings).
 * Certain tiles, such as Windows Media Player, have been removed - while other new tiles get added.
 * MyTVApp now functions again - however there no longer is an Avalon Trust Manager pop-up, and it isn't as functional as before.
 * This is the earliest available build to include the Segoe UI font, which was also incorporated in post-reset builds of Longhorn and later Microsoft operating systems.

Hidden dialogs
There are a few dialogs that cannot be accessed normally. They are:


 * Security preferences - Allows you to set preferences for security. It does not seem to have any effect.
 * Installer warning dialog - Asks for your permission on whether to run an installer or not that is not trustworthy.
 * File resolve dialog - A new dialog that appears whenever a new file moves to a specific place where another file with the same name and file extension already exists.
 * Help and Support Center - There is an early version of the Help and Support Center in this build, it can be opened by running.

Hidden sidebar tiles
There are a few sidebar tiles that are disabled by default in this build. They are:


 * RMA Test Tile - In this build, it only shows the title of the tile, and nothing else is there.
 * Longhorn Status - By default links to
 * Messenger Status Tile - This tile only works if you are using Windows Messenger. You cannot use MSN Messenger with this tile. Also, this tile does not work with Windows Messenger 4.0, you will need 4.6 or 4.7 for it to function correctly.

Installation

 * On some installs, once copying files has completed, setup will fail to create a  file. Although booting will still be possible,   will default to.
 * The hardware detection portion of setup may crash, and an error message may appear as well. Simply press ALT+TAB to access the error message, and click OK.
 * On some ISO files, the MBR, also known as the boot sector is corrupt.

Upgrading

 * On some machines when logging in after the first reboot when upgrading from Windows Longhorn build 4017 the system will bugcheck with the code.

Desktop Compositing Engine
This build includes two generations of the Desktop Compositing Engine. While the build is configured to use the new one out of box, initialization fails because  is missing from , to correct this you'll need to copy the DLL from. Additionally,  is required to control new DCE — this is not present in the build itself. Build 4029 (main)'s  can be patched to work with this early implementation.

First generation DCE in this build supports two variants: one is the full window transparency like in build 4015 (main) and build 4017 without a patched ; two is the glass-style frames identical to those in build 4015 (main) and build 4017 with a patched. To revert the old DCE implementation you'll need to do the following:
 * Import this .reg file:
 * Reboot
 * Go into Display Properties
 * Click the Advanced... button in the Settings tab
 * Click Enable Now

General

 * The Microsoft Windows Storage Engine crashes upon logging in.