Windows 8 build 7850

Windows 8 build 7850 is a Milestone 1 build of Windows 8. It is currently the earliest leaked build of Windows 8. On 2011-04-12, this build was first leaked as an Enterprise SKU image, then only much later, in 2015-01, additional SKUs were leaked.

Being early in development, many areas still says Windows 7 and the kernel is still 6.1 (in a similar manner to XP build 2202 and build 2211, 8.1 build 9299 and 10 build build 9780 and 9785). The default background image of this build is a blueish gradient with the note not to leak this version ("shhh... let's not leak our hard work").

Features
Note: Most new features must be unlocked via registry editing.
 * Explorer Ribbon UI (Icons are all circles)
 * Centered title bar text
 * Built-in PDF Reader (basic)
 * New/Modern Task Manager (partially broken)
 * Webcam Application (fullscreen)
 * Auto colorization of themes
 * ApplicationExplorer (for early start screen?)
 * Aero Lite (basic)
 * Early beta of IE9
 * System reset (sysreset.exe)
 * Portable workspace creator (pwcreator.exe)

PDF Reader
While there is a very early version of the built-in PDF Reader included, it is disabled by default. It can be enabled using the following registry script: Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Applets\Paint\Capabilities] "CLSID"="{D3E34B21-9D75-101A-8C3D-00AA001A1652}" and then running  with any PDF file as an argument (or without any argument to open a blank page). It is not required to disable Aero to run the PDF Reader.

Modern Windows Task Manager
A preliminary version of the Modern Windows Task Manager is included as well. To enable it, run the following registry script: Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\TaskUI] "TaskUIEnabled"=dword:00000001 and then open.

Ribbon UI
A Ribbon version of Windows Explorer is included as well. To enable it, use the following registry script: Windows Registry Editor Version 5.00 [HKEY_CLASSES_ROOT\CLSID\{4F12FF5D-D319-4A79-8380-9CC80384DC08}] "AppID"="{9198DA45-C7D5-4EFF-A726-78FC547DFF53}"

Webcam Capture Application
An early version of the webcam capture application is included as well. To enable it, run the following registry script: Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\GRE_Initialize] "RemoteFontBootCacheFlags"=dword:0000100f and then run.

Auto Colorization
Create a copy of a theme from, add   to the end of the   section and apply.

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.