Windows 8 build 7850

Build of Windows 8
Release nameMilestone 1
OS familyWindows NT
Version number6.1
Build number7850
Build revision0
Architecturex86, x64, ARM32
Build labwinmain_win8m1
Compiled on2010-09-22
Expiration date
Timebomb2011-02-05 (+136 days)
About dialog
Win8 Build7850 Winver.png
TCB.png TCBGallery.png BA.png

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,[1] 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.[2] It is the earliest available build of Windows 8 compiled for the x86 architecture. Files from the ARM32 compile of this build were discovered on the Microsoft Symbol Server on 24 May 2022.

It is the last available build of Windows 8 that mostly uses the Windows 7 branding and the 6.1 kernel version.

This build utilizes a valid SHA-1 production-signing certificate (signed by the Microsoft Windows Verification PCA certificate chain, associated with Windows Hardware Quality Labs (WHQL)) and can be booted and installed on the current date.

A screenshot of the Simplified Chinese language pack for this build was uploaded onto the Chinese forum Baidu Tieba on 12 June 2020.[3]

Editions and keys[edit | edit source]

Edition / SKU Key
Starter 7Q28W-FT9PC-CMMYT-WHMY2-89M6G
Home Premium RHPQ2-RMFJH-74XYM-BH4JX-XM76F
Professional HYF8J-CVRMY-CM74G-RPHKF-PW487
Enterprise H7X92-3VPBB-Q799D-Y6JJ3-86WC6

New features and changes[edit | edit source]

Internet Explorer[edit | edit source]

The new Internet Explorer 9 user interface is now enabled by default; there is no longer a need to patch the application in order to enable the new UI.

Redpill[edit | edit source]

This build's Metro is almost identical to the previous build. The Start screen has a yellow-orange background in debug compilations of this build instead of the white background seen in free compiles. As of 2024, the reason behind this is unknown, but it is possibly made to test the accent color.

Other features[edit | edit source]

  • Support for 32-bit UEFI boot
  • Support for booting from an exFAT partition
  • 4K Native logical sector boot
  • Hybrid boot

EULA Hash / Hash ID[edit | edit source]

shell32.dll has code to print the hash ID in the about box and desktop watermark, which appears to fail in this build (hash ID is only printed if the function to obtain it succeeded). The public symbols for this build give a mangled name for this function as bool GetEulaHash(wchar_t*, size_t), although compiler or link-time optimizations removed and inlined the second argument (length of output string buffer in characters). The function retrieves the default value in the registry key HKLM\SYSTEM\WPA\478C035F-04BC-48C7-B324-2462D786DAD7-5P-9. This value must be REG_BINARY of size 128 bytes; this data is split into eight 16-byte buffers, Hash[n] is equal to the nth byte of each of the buffers XORed together.

Bugs and quirks[edit | edit source]

General[edit | edit source]

  • On some machines, installing this build is not possible due to a 0x7F bugcheck.
  • Some graphics drivers may prevent the system from booting and will result in an ATTEMPTED_EXECUTE_OF_NOEXECUTE_MEMORY or a SYSTEM_SERVICE_EXCEPTION bugcheck.

Installation[edit | edit source]

  • On some machines, upgrading to this build is not possible due to an error when booting into the OOBE.
  • The last word of status messages shown when starting Setup and before the computer reboots into OOBE is cut off.
  • Setup may hang when restarting after the hardware portion. Restarting the machine will fix it.

DWM and Aero[edit | edit source]

  • Due to changes that are incompatible with the graphics stack, to get the Aero functionalities to work on VMware Workstation versions 14.0 and above, set hardware compatibility to Workstation 9.x. However, Aero doesn't persist when logging off and logging back on.
  • 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. This bug persists until build 7978.

Windows Explorer[edit | edit source]

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

Internet Explorer[edit | edit source]

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

Gallery[edit | edit source]

English version[edit | edit source]

Setup[edit | edit source]

Interface[edit | edit source]

Redpill-specific[edit | edit source]

Simplified Chinese language pack (unavaliable)[edit | edit source]

References[edit | edit source]