Windows 8 build 7700

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, not like how they were signed under the standard "Microsoft Corporation" banner during the development of Windows 7. This build 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 build was jointly leaked by BetaWiki Discord members lucasm and Wheatley on 2019-12-25.

The unfathomably early version of Internet Explorer 9 (still acknowledged in the application as being 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.