This article describes an update that adds the volume license key support for Windows Server 2012 Essentials. After you install the update, Key Management Server (KMS) activation support is available for Windows Server 2012 Essentials.
Cumulative Update information
To resolve this issue, install the Windows 8 and Windows Server 2012 cumulative update 2822241. For more information about how to obtain this cumulative update package, click the following article number to view the article in the Microsoft Knowledge Base:
2822241 Windows 8 and Windows Server 2012 cumulative update: April 2013
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about software update terminology, click the following article number to go to the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates