You want to determine if the KCC is completing successfully.
Open the Event Viewer of the target domain controller.
Click on the Directory Service log.
In the right pane, click on the Source heading to sort by that column.
Scroll down to view any events with Source: NTDS KCC.
The following command will display any KCC errors found in the Directory Service log:
> dcdiag /v /test:kccevent /s:<DomainControllerName>
The only way to debug issues with the KCC is by looking for NTDS KCC events in the Directory Service event log. If you suspect a problem or perhaps are seeing errors, you can increase the amount of logging in the event log by enabling diagnostics logging for the KCC. When the KCC diagnostics logging is enabled, each KCC exception logs a lot of information to the event log that may help you pinpoint the problem. See Recipe 15.2 for more information on enabling diagnostics logging.