What was happening to us is that different machines would report in as each other. I.E. pc1 would report in and be in the list, but pc2 was not. Then pc2 would report in and be in the list but pc1 would not. Whoever reported last would be the only one in the list (which makes sense if you think about it).
But Hah, gotcha! Generating a new SID won't fix the problem with WSUS. WSUS generates it's own ID based on the SID. Here's the full proceedure I gave to the service desk:
1. Run newsid.exe, allow the pc to reboot.
2. Using regedit, delete the following registry keys:
HKLM\Software\Microsoft\Windows\Current Version\Windows Update\SusClientId
HKLM\Software\Microsoft\Windows\Current Version\Windows Update\SusClientIdValidation
3. Stop then restart the Automatic Updates service on the pc.
4. From a command prompt, enter the following:
wuauclt.exe /resetauthorization /detectnow
The client should report in to WSUS within 10 - 20 minutes.
Deleting those registry keys forces the WSUS client to generate a new ID.
hth.
--
The stagehand's axiom: "Never lift what you can drag, never drag what you can roll, never roll what you can leave.