If you use Windows templates and Windows Update Services, you could see a weird behaviour inside Windows Update Services.

Figure this scenario: from the same template, you created three servers Server1, Server2 e Server3. By turns, only one of these servers appears in WUS, and then it disappears in favor of one of the others.

that’s what is happening: all three servers has the same SusClientId, and when each of them contacts WUS to update its status, this value overwrite the previous one. From WUS point of view, is like the same server changing hostname and patch status.

To solve this problem, run this command in a shell on all the windows servers:

net stop wuauserv
REG DELETE "HKLMSOFTWAREMicrosoftWindowsCurrentVersionWindowsUpdate" /v AccountDomainSid /f
REG DELETE "HKLMSOFTWAREMicrosoftWindowsCurrentVersionWindowsUpdate" /v PingID /f
REG DELETE "HKLMSOFTWAREMicrosoftWindowsCurrentVersionWindowsUpdate" /v SusClientId /f
net start wuauserv
wuauclt /resetauthorization /detectnow

The three delete commands on regedit can fail, since those keys can be absent.