Jeff Wouters's Blog

When you’re implementing a KMS infrastructure in your Windows 7 environment, it is possible you get an “Unable to connect to the WMI service on the remote machine” when you are using the Volume Activation Management Tool (VAMT) to update clients with the correct license keys.

After some searching, I found multiple causes, such as firewall settings (Windows Management Instrumentation (WMI) needs to be allowed through the firewalls in the clients) and port 1688 (default KMS port) needs to be allowed on the KMS host.

Still, I received the previous mentioned error…

The solution was to be found in the Windows DCOM security settings.
These are the actions you need to take to resolve this issue on your Windows 7 clients:

• Start “dcomcnfg.exe”.
• Goto “Component Services” –> “Computers”.
• Right click on “My Computer” and select “Properties”.
• Goto the tab “COM Security”.
• Click on “Edit Limits” under “Launch and Activation Permissions”.
• Select “Everyone”.
• Make sure that “Allow” is enabled for “Local Launch”, “Remote Launch”, “Local Activation” and “Remote Activation”.
  Note: By default “Local Launch” and “Local Activation” are already enabled.