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.

Hidden features
The following hidden features have been found within this build:


 * New tray clock user interface - enabled by creating key  under
 * Hidden lock screen - enabled by setting  to 1 under
 * Return to the old Start menu - set  to 0 under
 * New volume flyout - enable by setting  to 1 under

Hidden apps
There are a few hidden apps in this build:


 * Windows Default Lock Screen - accessed by running
 * Cloud Experience Host - accessed by running
 * Print Dialog - accessed by running
 * Windows Shell Experience Host - accessed by running

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

Incorrect window thumbnail border color
If window auto-colorization is enabled, the window thumbnail borders on the taskbar do not change color even after the wallpaper changes. This issue can be remedied by manually changing the window color through the Control Panel or restarting Windows.