Windows 10 build 9821

6.4.9821.0.fbl_partner_eeap.140820-0938
	Build of Windows 10
OS family	Windows NT
Version number	6.4
Build number	9821
Build revision	0
Architecture	x64
Build lab	fbl_partner_eeap
Compiled on	2014-08-20
Expiration date
Timebomb	2015-02-15 (+179 days)
About dialog

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 WinClub.pl published a screenshot of this build on 18 September 2014.^[1] The build was later uploaded publicly on 11 May 2020.

Editions and keys[edit | edit source]

Edition / SKU Name	Key
Core	334NH-RXG76-64THK-C7CKG-D3VPT
Professional	XHQ8N-C3MCJ-RQXB6-WCHYG-C9WKB
ProfessionalWMC (edition upgrade only)	GBFNG-2X3TC-8R27F-RMKYB-JK7QT

New features and changes[edit | edit source]

Disk format dialog[edit | edit source]

The disk format dialog functions again after it was broken since Windows 10 build 9785, and the option to create a MS-DOS boot disk was removed. However, it is not possible to verify that earlier builds haven't removed this option, as the option wasn't removed from the dialog, and is removed at runtime instead.

Bugs and quirks[edit | edit source]

Setup[edit | edit source]

The Windows logo displayed in the autorun is heavily brightened and utilizes a grey background not matching with the purple one of the application.

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.