Troubleshooting: KMS server is not reporting the correct number of KMS clients

by Mitch Tulloch [Published on 18 Jan. 2012 / Last Updated on 15 April 2011]

How to troubleshoot a problem where your KMS server is not reporting the correct number of KMS clients on your network.

Scenario: You are using KMS to manage activation of volume-licensed Windows 7 computers on your networks. To deploy these computers, you've created a master installation and then cloned the master image using third-party tools. The cloned images were then applied to the client computers to deploy Windows to them. You now have 25 client computers deployed, but your KMS server is only reporting one activated Windows installation. What's wrong?

Resolution: You either forgot to run sysprep /generalize on your master installation before you cloned it to the computers on your network, or you set equal to 1 in the unattend.xml answer file used when you sysprepped the master installation. Either way, the result is that all your deployed computers have the same Client Machine ID (CMID), and  since KMS clients are identified by their CMIDs which are supposed to be unique to each computer, your KMS server only sees one KMS client on the network.

Do not try to fix the situation by running the slmgr.vbs /rearm command on each computer, for while doing this will provide each computer with a unique CMID, running this command will leave your computers in an unsupported state as it doesn't have the same result as running sysprep /generalize on the computers. The only supported way of resolving with this problem is to run sysprep /generalize on your master installation and then clone the generalized image and redeploy it to your computers. And either set equal to 0 or remove it entirely from the unattend.xml file used by sysprep.

Mitch Tulloch is a seven-time recipient of the Microsoft Most Valuable Professional (MVP) award and widely recognized expert on Windows administration, deployment and virtualization. For more tips by Mitch you can follow him on Twitter or friend him on Facebook.

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