Before Active Directory starts it will do an inital sync with the other domain controllers. This can take several minutes if the other DC are offline. i.e in an test enviroment.
Add the registry value below and reboot the DC in question. When it comes back up, it will not require the init sync before successfully advertising itself and doing its job.
“Repl Perform Initial Synchronizations”=dword:00000000
For the above entry, 1 means “do it” while 0 means “do not do it”.