Key Management Service (KMS) uses a KMS key to activate KMS on a KMS host, and to establish a local activation service in your environment. This service can activate Windows Vista and Windows Server 2008 on computers that are connected to the KMS host computer. This update extends support for KMS to provide activation for Windows 7 and for Windows Server 2008 R2.

Note: If a KMS key that supports Windows 7 and Windows Server 2008 R2 is used to provide activation before this update is applied, the KMS key cannot be installed after you apply this update. If you try to install this KMS key after you apply this update, you receive the following error message:

Error: 0xc004f050 The Software Licensing service reported that the product key is invalid


A KMSCLIENT activation computer does not utilize the ActivationInterval sent from a KMSHOST and submits Activation requests based on the default schedule.


Key Management Server: Part of Microsoft Volume Activation 2.0 that is used to activate volume-licensed Microsoft products locally instead of directly with Microsoft.


You try to activate a new Windows Vista-based client computer. If the client computer is hosted by a computer that is running the Key Management Service (KMS), the client computer may not be activated successfully. Therefore, the computer is not added to the KMS pool. Instead, you receive the following error message:


The computer could not be activated. The returned count from your Key Management Service is insufficient.

ITsVISTA Web Links: May 16th, 2007


When you run the Slmgr.vbs script on a Key Management Server (KMS) computer, you verify that the number of client computers does not increase when you add new Windows Vista-based client computers to the network. Additionally, you may see the following event in the Key Management Service event log for each new Windows Vista-based client computer that you add to the network:

Log Name: Key Management Service
Source: Microsoft-Windows-Security-Licensing-SLC
Event ID: 12290
Level: Information
Description: An activation request has been processed.
When you run the Slmgr.vbs script together with the –dli argument, the client computer count information does not increase as expected. In the following event that is logged in the Key Management Service event log, the current count remains the same:

Name: Windows(TM) Vista, Enterprise edition
Description: Windows Operating System – Vista, VOLUME_KMS channel
Partial Product Key: XXXXX
License Status: Licensed

Key Management Service is enabled on this machine
Current count: 1
Listening on Port: 1688
DNS Publishing: Enabled
KMS priority: Normal