Windows 8 build 8400

6.2.8400.0.winmain_win8rc.120518-1423
	Build of Windows 8
Release name	Release Preview
OS family	Windows NT
Version number	6.2
Build number	8400
Build revision	0
Architecture	x86, x64, ARM32
Build lab	winmain_win8rc
Compiled on	2012-05-18
Expiration date
Timebomb	2013-01-15 (+242 days)
About dialog

Windows 8 build 8400 is the official Release Preview build of Windows 8, which was officially released to the general public on 31 May 2012.^[1]^[2] The Simplified Chinese language variant was leaked across different Chinese forums two days ahead of the official debut.^[3]

The ARMv7 compile of this build was showcased on a Channel 9 blog post titled Developing for Windows on ARM,^[4] and was distributed to partners engaging in the Ecosystem Engineering Access Program (EEAP).^[5] Its components were additionally released in the form of a set of Repair Content Packages,^[6] which are used by DISM /Cleanup-Image /RestoreHealth to repair an existing Windows installation.^[7]

Editions and keys[edit | edit source]

Edition / SKU Name	Key
Core	2H7NK-3VJJY-HHY3Y-WM3T8-JFCRY
Professional	GCNRF-BHBCM-W9YWM-VWQP6-TJBWR
ProfessionalWMC (edition upgrade only)	MBFBV-W3DP2-2MVKN-PJCQD-KKTF7

Changes[edit | edit source]

User interface[edit | edit source]

Only minor differences can be observed across the user interface when compared against the previous build: the bug preventing task previews from displaying within the Windows shell has been fixed, and the Desktop Window Manager client area in Windows Explorer no longer extends to the navigation bar when the Ribbon user interface is not utilized. The spacebar key can now be used to dismiss the lock screen.

Minor visual changes to existing assets have also been introduced: the wallpaper first introduced in build 8375 has had its color temperature and saturation slightly adjusted, and the Windows Update icon has been updated to utilize its final design.

Bugs and quirks[edit | edit source]

Intel Sandy Bridge CPU deadlocks[edit | edit source]

This build suffers from a clock timing-related hardware abstraction layer (HAL) bug that causes the operating system to gradually deadlock when it is run on Intel processors based on the Sandy Bridge microarchitecture while the system is installed on a solid-state drive.^[8]

The KB2727113 update resolves the bug by replacing the HAL with a fixed version from the following GDR/LDR compiles:^[9]

6.2.8400.114 (winmain_win8rc_gdr.120625-1503) (GDR)
6.2.8400.4219 (winmain_win8rc_ldr.120624-1501) (LDR)

Aero Lite transparency effects[edit | edit source]

When using the Windows Basic (Aero Lite) visual style, transparency effects can be enabled through the use of a bug in the Personalization Control Panel. To do so:

Right-click the desktop and open up Personalization, then click on the "Window Color" link given at the bottom of the window. Keep the window open.
Open a separate personalization window and apply the Windows Basic theme.
Switch to the other personalization window that was opened at the start, uncheck and re-check the "Enable transparency" option and then click on the "Save changes" button. This will cause transparency effects to take effect.

Gallery[edit | edit source]

Out-of-box experience[edit | edit source]

Personalization
Express settings
Microsoft account page
Local or Microsoft account page
Local account page
Finalizing settings
First logon animation

Interface[edit | edit source]

Boot screen
Login screen
Start screen
Charms bar
Windows Basic (Aero Lite) visual style
Windows Basic (Aero Lite) visual style with transparency effects by means of a bug in the Personalization Control Panel