Windows 8 build 7989

Windows 8 build 7989 is a Milestone 3 build of Windows 8. It was leaked on 2011-06-18.

Features

 * Immersive Internet Explorer
 * Metro login screen
 * Immersive Control Panel
 * Immersive Reader (broken)
 * Charms bar
 * MS Help

EFI
This build appears to not support hardware with EFI, and will require slightly older, BIOS-based hardware to run (or virtualisation software, like VirtualBox or VMWare).

Aero
This build appears to have a slightly broken Windows Aero theme, with only the top portion of the window frame using the blur effect, leaving the side borders transparent. In this build however, the bug does not occur if Redpill is unlocked.

Redpill
Using the MetroUnlocker tool released for build 8056, some Metro features are unlocked, primarily a notably different Charms bar (resembling early Windows 8 concepts compared to the Charms bar found in newer builds), Immersive app execution (so the Immersive Control Panel, Immersive Browser, and MS Help will launch and function normally), and partial Metro search functionality (settings and file searches will work, but attempting to search for an application will cause explorer to crash). However, the unlocked features are very unstable, especially as the start screen, while technically enabled, is broken due to some incompatible functions. As such, by default, after running MetroUnlocker, Windows Explorer will be in a crash loop, as explorer will try to load the start screen at login. To fix this, you could either boot into safe mode (as explorer will not attempt to load the start screen) or you could delete  from the System32 folder, which will disable the start screen and allow Windows to boot normally, albeit with the Windows 7 start menu and the Start charm still broken.

Start screen
BetaWiki Discord member Distort managed to unlock the start screen of this build.