Ever have issues activating windows 7 via KMS?

Windows Key Management Server or KMS as it is known is normally a very simple affair. You install the KMS server, the servers find KMS server via DNS and everything works. Most of the time….


I have read that sometimes when cloning is used the process does not go as smoothly. Recently I ran across this at a client in California, the issue that prevented the KMS server from working was related the the Client Machine ID (CMID) not being unique. KMS will not increase the count (which for client based OS needs to be 25 before it will start activating windows) and the end result is a bunch of workstations that are in grace period and eventually leaving users stranded.

The fix is to either run the /REARM command or just make sure the golden image has had sysprep run with the Generalize option.


you can view the CMID by filtering the event logs for Event ID 12288


The string of text that ends before the date is the CMID, this will be unique when you generalize the image.

Here is the microsoft KB article for more info:


Here is a good guide on troubleshooting this issue:


Here are a few commands i found helpful:

  • Apply a new product key on the machine:

slmgr.vbs /ipk <insert the proper KMS key here>

  • Specify a KMS server (when your DNS isnt clean yet):

slmgr.vbs /skms <FQDN of your KMS server here>

  • Force the activation process:

slmgr.vbs /ato