You might notice that some computers are appearing multiple times in WSUSAdmin - Computers and some of them disappear very often. This is due to duplicate SUS client IDs. Take a look at this script which deletes duplicate SUS client IDs found on a computer. These IDs are often found on computers where the operating system was installed using an image-based setup.
@echo offEcho Save the batch file "AU_Clean_SID.cmd". This batch file will do the following:Echo 1. Stops the wuauserv serviceEcho 2. Deletes the AccountDomainSid registry key (if it exists)Echo 3. Deletes the PingID registry key (if it exists)Echo 4. Deletes the SusClientId registry key (if it exists)Echo 5. Restarts the wuauserv serviceEcho 6. Resets the Authorization CookieEcho 7. More information on http://msmvps.com/AthifPause@echo onnet stop wuauservREG DELETE "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate" /v AccountDomainSid /fREG DELETE "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate" /v PingID /fREG DELETE "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate" /v SusClientId /fnet start wuauservwuauclt /resetauthorization /detectnowPause
SUS client ID will be generated at next detection.