Windows 10 build 9900

Windows 10 build 9900 is a build of Windows 10, which was uploaded to BetaArchive on 29 January 2015.

It is the earliest available build of Windows 10 to be compiled in the  branch.

Taskbar

 * The taskbar design has been changed to a flatter style and now uses the black color seen in the RTM.
 * Taskbar search has been improved with the addition of a text box.
 * Security and Maintenance icon on the taskbar has been removed.

Cortana

 * Cortana has been added.

Windowed Metro

 * The window design has changed to a more modern style.

PC Settings and the Control Panel

 * PC Settings has an updated homepage.
 * Update Center has been removed from Control Panel.

Charms Bar

 * Charms bar received a minor update.
 * Settings section has been removed from it.

Desktop

 * The "Welcome to Tech Preview" desktop shortcut has been removed.

BIOS support
This build can only be installed on machines utilizing UEFI firmware since it hangs on a BIOS system.

Window thumbnail color error
Window thumbnails on the taskbar do not change color, but the user can change it after the computer restarts.