•Enable ETL Verbose Logging from the \Program Files\System Center Operations Manager\Tools Directory by running StartTracing.cmd VER (it is case sensitive)
•Start the OpsMgr Health Service. It'll fail.
•Turn off ETL Verbose Logging from the \Program Files\System Center Operations Manager\Tools Directory by running StopTracing.cmd
•Evaluate the ETL Logs for Health Service
In my case this key was missing:
It should point to the location in which the agent is installed and the Health Service State subdirectory (\Program Files\System Center Operations Manager\Health Service State). If it is not modify the key. If the key is not present, add the key.
Also check for the following registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\HealthService\Parameters\Management Group\<Management Group Name Here>\Windows AccountLockDownSD.
If the WindowsAccoundLockDownSD is not present, export is from a running machine and import is to the bad machine. You could also import it from the operations manager server (this is what I tried).
•Start the OpsMgr Health Service, it should start at point.