Symptoms
Client count is not incrementing on your KMS server as seen during standard troubleshootingYou have 25 or more client systems with the appropriate client key installed.You are utilizing ClonePrep (for instant clones) or QuickPrep (for linked clones)In the Event Viewer on the KMS server you see that all the newly provisioned machines are showing the same Client Machine ID (CMID). Event ID 12290 Note, this matter will also impact machines that have not had sysprep /generalize run See KMS Host Client Count not Increasing Due to Duplicate CMID’S for more details.
Cause
VMware QuickPrep and ClonePrep creates virtual desktops that have the same CMID as the parent image. When the Client Machine ID (CMID) is the same on multiple virtual machines, Microsoft KMS may not acknowledge the systems as individual systems. This, in turn, will not allow the KMS client count to increment.
Resolution
Use Microsoft Sysprep with Horizon linked clones and instant clones. Sysprep enables children clones to have unique CMID from the parent image.
For instant clones, Sysprep is only supported from Horizon 2106 or later. Horizon 7.x does not support Sysprep for instant clonesFor linked clones on Horizon 7.x, Sysprep is supported
For instant clone, ClonePrep for both mode A and mode B result in identical CMID of children clones. Only through the use of SysPrep can unique CMID be generatedMore information on the various customization methods available for Horizon can be found: https://kb.vmware.com/s/article/2003797
Workaround
There are two ways to resolve the situation:
You can switch to Sysprep to deploy systems. This creates new Client Machine ID (CMID) and SIDs for newly deployed virtual machines.
Once an instant clone or linked clone desktop has been created, you can utilize a /rearm command and a machine restart to set a unique Client Machine ID (CMID). Note, this will also reset the activation timer. These steps can be repeated to increase the count above the required 25 to activate. Details on how to implement this are detailed in Microsoft Documentation on this matter. Note: Once the virtual machine is rebooted, the change may not be immediate. It may take approximately 30 minutes for the client to register on the KMS server.
Related Information
Windows 7 KMS activation fails on View virtual desktopsDifferences between VMware ClonePrep, QuickPrep and Microsoft Sysprep
