Windows 8 build 7850

Windows 8 build 7850 is the official Milestone 1 build of Windows 8, which was originally uploaded to BetaArchive as an x86 Enterprise SKU version on 12 April 2011, then on 17 January 2015, an x64 version of this build was uploaded to the aforementioned website along with additional SKUs for both the x86 and x64 architectures and its server counterpart. It is the earliest known x86 available build of Windows 8.

Due to its earliness, many areas still say "Windows 7" and the kernel version is still 6.1 (much like builds 7700, 7746 and 7814).

Files from the ARM32 compile of this build were discovered on the Microsoft Symbol Server on 24 May 2022.

Internet Explorer
The layout of Internet Explorer 9 has been updated to resemble that of the final version, albeit with some visual differences.

Redpill
This build's Metro is almost identical to the previous build. For unknown reasons, the Start screen has a yellow-orange background in debug compilations of this build instead of the white background seen in free compiles.

Other features include:
 * Support for 32-bit UEFI boot
 * Support for booting from an exFAT partition
 * 4K Native logical sector boot
 * Hybrid boot

General

 * On some machines, it is not possible to install this build due to a  bugcheck.
 * Some graphics drivers may prevent the system from booting and will result in an  or a   bugcheck.

Installation

 * On some machines, it is not possible to upgrade to this build due to an error when booting into the OOBE.
 * The messages shown when the setup is starting or restarting the computer have the last word cut off.
 * The original upload of this build from 2011 is bundled with the Windows 7 RTM pre-installation environment.
 * Setup may hang when restarting after the hardware portion. Restarting the machine will fix the problem.

DWM and Aero

 * The Windows Basic and the High Contrast themes do not properly render due to the enforcement of the DWM Aero theme.
 * The Aero functionalities do not work on VMware Workstation versions 14.0 and above due to changes that are incompatible with the graphics stack.
 * 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.

Windows Explorer

 * Changing the date has a chance of crashing the Explorer shell.
 * Using Desktop Gadgets significantly slows the OS down.

Internet Explorer
Like build 7700 and build 7814, the Internet Explorer 9 Beta engine is unstable and may crash when accessing HTML5 websites.