KMS Server won't activate additional servers

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I have had my KMS server up and running for several years without any problems.  Recently I was working on a new 2008 Standard Server and it wouldn't activate.

I attempted to first use the standard GUI on the Windows Activation screen.  I was even surprised it popped up since KMS usually just works.  I selelcted "Activate Windows online now", a few moments later it came back with the response "The Product key you typed is already in use".

What does that mean? So I thought: forget it, I'm jumping to an elevated command line.

I ran slmgr -ato and I got the message it was activating and waiting for a click on the Ok button.  This was followed by the error message (What can't they open up a window within the program???).

Run 'slui.exe 0x2a 0xc004C008' to display the error text. Error: 0xC004C008

So I ran it as requested:

An error has occured
Code: 0xC004C008

Description: The activation server determined that the specified product key could not be used.

Finally something to work with.  It turns out there are limits placed on your KMS server and you have to contact Microsoft to get your KMS server limits increased.  So my sales rep and I contacted Microsoft Licensed Support at 1-866-230-0560.

They requested we send an upgrade request to the address

Ask for an increase in X number of activations on the key with the following details included:

  • Enrollment Number:
  • Company Name:
  • # of Activations:
  • KMS Key to modify:

It sure would have been helpful if Microsoft could have just said, "Hey Dude you have used up all your KMS licenses.  Please contact your local sales rep to get your count increased."

I have now gone through the requested steps and emailed my request but I still have to wait up to two business days for it to complete.

The email response from their robot:

Thank you for your request for additional KMS activations. You can expect to receive a response within two business days.

All support and responses provided through this alias will be in English.

Please reference Case ID:xxxxxxx for any questions regarding this request.


Hopefully the tags on this page help others to quickly solve this problem.

Thanks to Josh Bussiere for his assistance.