Windows 8 build 7700 is a pre-Milestone 1 build of Windows 8. Screenshots of this build were released by the Russian Windows news website WZor on 2010-01-29. 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 and not Windows 7 SP1. 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 reuses the "betta fish" default wallpaper seen in development builds of Windows 7.
The power service has been given a large overhaul, with the User-mode Power Services Extension DLL (umpoext.dll) one of several DLLs added in this build, persisting to this day in Windows 10. Additional APIs were also added for Audio and Bluetooth services. The On-Screen Keyboard was internally updated, with some functions being separated out into osksupport.dll.
Additional error messages were added to System Restore.
The build was jointly leaked by BetaWiki Discord members lucasm and Wheatley on 2019-12-25.
The early version of Internet Explorer 9 (still branded as Internet Explorer 8) in this build is extremely buggy and will often instantaneously crash when switching to IE9 mode or loading a page containing HTML5 content.
