When you are using Templates in VMWare or just do clone a machine which was connected to a WSUS server before, you might get dupplicated WSUS client ID’s

You will notice those mchines will not show up in the WSUS console

 

WSUS Log for troubleshooting

%windir%\WindowsUpdate.log

Stop the Service

Net stop wuauserv

Delete registry keys

In

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate

Delete those two keys

SusClientId

SusClientIdValidation

Restart the service

Net start wuausrv

Reregister the client:

WUAUCLT /ResetAuthorization /DETECTNOW