Windows Server 2012 build 7861

6.1.7861.0.fbl_core1_hyp_dev.101013-1700
	Build of Windows Server 2012
OS family	Windows NT
Version number	6.1
Build number	7861
Build revision	0
Architecture	x64
Build lab	fbl_core1_hyp_dev
Compiled on	2010-10-13
Expiration date
Timebomb	2011-02-05 (+115 days)
About dialog

Windows Server 2012 build 7861 is a build of Windows Server 2012. It was shared on 11 October 2024, along with its client counterpart from the fbl_grfx_dev1 branch.

This is the latest available build to use the Windows Classic theme by default, and it is more functional here than in its client counterpart (until Aero theme is applied). It is also the last available build to use the kernel version 6.1.

Editions and keys[edit | edit source]

Edition / SKU	Key
Standard + StandardCore	HMG6P-C7VGP-47GJ9-TWBD4-2YYCD
Enterprise + EnterpriseCore	7P8GH-FV2FF-8FDCR-YK49D-D7P97
Datacenter + DatacenterCore	7X29B-RDCR7-J6R29-K27FF-H9CR9
ServerWeb + ServerWebCore	YGTGP-9XH8D-8BVGY-BVK4V-3CPRF

Changes[edit | edit source]

Leak prevention[edit | edit source]

A near-final implementation of the Windows Fingerprinting Service has been added through the addition of a dedicated fingerprinting blob in the system, displayed on the desktop watermark and the Version Reporter Applet by shell library shell32.dll. The fingerprint is directly appended at the end of the BuildLab string (queried from registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion) in the form of a build hash (officially named the "EULA hash"), computed by splitting the WFS blob into 8 arrays of 16 bytes and XORing each of the 16 bytes together. The EULA hash can then be derived in order to source build leaks to existing Microsoft affiliates; the visibility of the EULA hash and the confidentiality warnings depend on the presence of certain compiler flags.

Fingerprinting data is now stored in the registry key HKLM\SYSTEM\WPA\478C035F-04BC-48C7-B324-2462D786DAD7-5P-9. The registry key must exist in the Windows install, or the operating system will either refuse to boot or non-deterministically bugcheck with codes KERNEL_SECURITY_CHECK_FAILURE (during boot) or CRITICAL_STRUCTURE_CORRUPTION (if the periodic WFS check during runtime fails). Furthermore, most parts of the fingerprint data are now encrypted, and therefore require reverse engineering efforts to decode and extract the relevant information.

Bugs and quirks[edit | edit source]

Installation[edit | edit source]

The last word of status messages shown when starting Setup and before the computer reboots into OOBE is cut off.

Blank charms bar[edit | edit source]

If the Windows Classic theme is used, the charms bar will appear to be blank.

General[edit | edit source]

The Windows Classic theme cannot be applied again after the user sets the theme to Aero.

Redesigned Server Manager[edit | edit source]

By default, the redesigned version of the Server Manager will not work, saying that it can't connect to the destination server. This can be fixed by running winrm quickconfig and approving all changes, however doing that will result in another error.