Came across an interesting situation the other day. I was having servers in WSUS randomly change their WSUS group back and forth! Not cool, especially when you’re patching servers based on those groups and the wrong “Prod” box ends up in the “Test” group!!! After a good amount of Google searching I came across the solution to my problem. WSUS uses a few Registry values to track who each server is in its database. In my environment we’ve built most of our systems from a small handful of templates in VMware. Come to find out, those templates (or at least some of them) contained registry information that gave each VM deployed from that template THE SAME id in WSUS! Ah HA! This is easy enough to fix thankfully. Delete a few registry entries from the problem Server and reboot to create new ID’s of it’s own navigate to this site. Just a couple of PowerShell lines did the trick for me.
Remove-ItemProperty -Path REGISTRY::HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate -Name SusClientID
Remove-ItemProperty -Path REGISTRY::HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate -Name SusClientIDValidation