Windows 10 build 9821

Build of Windows 10
OS familyWindows NT
Version number6.4
Build number9821
Build revision0
Build labfbl_partner_eeap
Compiled on2014-08-20
Expiration date
Timebomb2015-02-15 (+179 days)
About dialog
TCB.png TCBGallery.png

Windows 10 build 9821 is a build of Windows 10, which was originally released to Microsoft partners participating in the Ecosystem Engineering Access Program (EEAP), as indicated by the fbl_partner_eeap branch. Polish website published a screenshot of this build on 18 September 2014.[1] The build was later uploaded publicly on 11 May 2020.

It is the first available build to introduce Windows Technical Preview branding.

Editions and keys[edit | edit source]

Edition / SKU Name Key
Core 334NH-RXG76-64THK-C7CKG-D3VPT
ProfessionalWMC (edition upgrade only) GBFNG-2X3TC-8R27F-RMKYB-JK7QT

New features and changes[edit | edit source]

Branding[edit | edit source]

This build uses the "Windows Technical Preview" branding on the desktop and "Windows" branding in winver instead of "Windows 8.1" and "Windows 8" in those areas respectively. However, on System Properties, the Windows 8 logo has been removed instead and thus, it does not feature any Windows logo.

Taskbar[edit | edit source]

  • Action Center, a Windows Phone-like notification area, has been added.
  • The Search button has been readded to the taskbar after being absent in Windows 95 build 81.
    • As part of this change, Cortana, which was a feature brought over from Windows Phone, has been added. It can be accessed from taskbar search.

Bugs and quirks[edit | edit source]

Metro UI[edit | edit source]

Dragging a window in full-screen mode in Metro apps will result in Metro UI transitions from Windows 8.1.

Internet Explorer[edit | edit source]

F12 Developer Tools may fail to launch.

explorer.exe error during shutdown[edit | edit source]

When the system shuts down, a memory access error related to explorer.exe may occur.

Timebomb[edit | edit source]

Like other builds found in the fbl_partner_eeap branch, this build uses a test-signed certificate and as a result can be installed on the current date. However, installing this build on the current date disables the ability to change the desktop wallpaper in the Control Panel.

Taskbar Language Bar[edit | edit source]

The language bar is not displayed on the taskbar, but however the old language bar is working properly.

Taskbar preview border color[edit | edit source]

If window auto-colorization is enabled, the taskbar preview borders 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 by restarting Windows.

File operation window metrics[edit | edit source]

The file operation progress window (which appears while copying, moving, and deleting files) may not extend automatically when more than one operation is in progress.

Closing notifications in the Notification Center[edit | edit source]

When swiping away all notifications from a system tray application, particularly the Action Center, explorer.exe will crash.

Gallery[edit | edit source]

References[edit | edit source]