. Because it is an unreleased development version, it is not available through official Microsoft channels but can be found in community archives. Available ISO Download Links You can find various versions of Build 7850 archived on the Internet Archive Standard 32-bit (x86) Enterprise : The original leaked version. Download from Internet Archive 64-bit (x64) and Check (chk) Builds : Includes both retail and debug versions of the build. Download from The Windows 8 Build Archive "Debombed" Version
Windows 8 Build 7850, known as Milestone 1, was the first version of Windows 8 to leak to the public in April 2011
Once you have secured the ISO via a safe download link, do not attempt to install it on your main PC. This is a pre-beta build from 2010. Drivers will not work properly, and the OS will expire via timebomb.
– BetaArchive, WinWorld, or MDL (My Digital Life) often have discussions and links, though you may need an account and meet download requirements (e.g., contributing verified dumps).