Windows 8 build 7700

Windows 8 build 7700 is the earliest available build of Windows 8, which was jointly shared by community members lucasm and Wheatley on 25 December 2019. Prior to its public availability, screenshots of this build were released by Russian Windows news website WZor on 29 January 2010. This build has been determined to be a Windows 8 build, due to its relatively high build number and presence of an extremely early version of Internet Explorer 9.

Assert strings have been changed to hide the full path, like in Windows 8. In addition, some executables are signed by "Windows Main Build Lab Account" like later Windows 8 builds, unlike the standard "Microsoft Corporation" signer during the development and release of Windows 7. This build also calls itself "Windows 8" in the "Local Group Policy" utility, in "Filter options". This build reuses the "betta fish" default wallpaper seen in Windows 7 builds 6910-7231 and the Windows 7 Release Candidate EULA. SSE is now required in order to run this build, dropping support for CPUs such as the Pentium II; although this is moot as there are no AMD64 CPUs that do not support SSE.

New features and changes
The power service has been given a large overhaul, with the User-mode Power Services Extension DLL being one of several DLLs added in this build, persisting to this day in Windows 10 and Windows 11. Additional APIs were also added for Audio and Bluetooth services. The On-Screen Keyboard was internally updated, with some functions being separated out into. Additional error messages were added to System Restore.

This is also the first build of Windows to require SSE instruction support to boot, and is therefore the first build to be unbootable in 86Box.

This build's Boot Manager introduces the following:
 * Boot debugging over serial improved with a driver for the Maxim MAX311 series (MAX3110E/MAX3111E/MAX3100/MAX3222E) SPI UART.
 * handles several architecture-specific relocations: IA64, ARM, Thumb, Thumb-2, and MIPS.
 * When loading a PE file that is required to be AMD64, attempting to load a Thumb-2 PE will now return.

Installation
It is not possible to upgrade to this build without modification due to setup being unable to copy files required for installation, because of a signature validation error.
 * To upgrade to this build, replace  in each index of   with a copy from build 7746.

Internet Explorer
The early version of Internet Explorer 9 (still branded as Internet Explorer 8) found in this build is known to be highly unstable and will often instantaneously crash when switching to IE9 mode or loading a page containing HTML5 content.