Windows 10 build 9903

10.0.9903.0.winmain_prs.141204-1736
	Build of Windows 10
OS family	Windows NT
Version number	10.0
Build number	9903
Build revision	0
Architecture	x86, x64
Build lab	winmain_prs
Compiled on	2014-12-04
Expiration date
Timebomb	2015-04-15 (+132 days)
About dialog

Windows 10 build 9903 is a build of Windows 10, which was shared online on 29 January 2015.^[1]

Editions and keys[edit | edit source]

Edition / SKU Name	Key
Professional	NKJFK-GPHP7-G8C3J-P6JXR-HQRJR
ProfessionalWMC (edition upgrade only)	GBFNG-2X3TC-8R27F-RMKYB-JK7QT
Enterprise	PBHCJ-Q2NYD-2PX34-T2TD6-233PK

New features and changes[edit | edit source]

Volume tray[edit | edit source]

The volume icon is now thinner and flatter in appearance, similar to that found in the RTM.

File Explorer[edit | edit source]

The default page in which File Explorer opens to can now be changed.
Home page has been renamed to Quick Access and it is expanded in the navigation tree by default.
Favorites page is now hidden in the navigation tree.

Miscellaneous[edit | edit source]

The new login screen first introduced in build 9845 has received an update.
XAML start menu now displays the user's name instead of the placeholder "Groot".
New pages have been added to the Get Started app.
Sync Settings have been updated.

Findings[edit | edit source]

New Action Center[edit | edit source]

A new Action Center has been added in this build. It is disabled by default and opens with the ⊞ Win+A keys.

To enable it, create and set UseActionCenterExperience to 1 under [HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\ImmersiveShell]

Hidden features[edit | edit source]

Network button actions in the tray center - enabled by setting ReplaceVan^[a] under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Control Panel\Settings\Network to 0, 1 or 2
- 0 – Enable a placeholder network flyout.
- 1 – Open directly to the Network settings page.
- 2 – Return to the Windows 8–like network flyout.

New tray clock user interface - enabled by creating key UseWin32TrayClockExperience under [HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\ImmersiveShell]
Hidden lock screen - enabled by setting Threshold to 1 under [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Authentication\LogonUI\TestHooks]
Enable XAML Start menu - create and set UseExperience to 1 under [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\ImmersiveShell\Launcher]
New volume flyout - enable by setting EnableMtcUvc to 1 under [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\MTCUVC]

Bugs[edit | edit source]

BIOS support[edit | edit source]

This build will only work on real hardware utilizing BIOS, unlike VMware which gives a CPU fault. On VMware, the user will need to use UEFI firmware.

Window thumbnail border color error[edit | edit source]

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.