How do I promote a Backup Domain Controller to the Primary Domain Controller?
A. When possible you should always promote a BDC to the PDC while the main PDC is still active, in this way the original PDC will be demoted to a BDC and no information will be lost, however sometimes the PDC will not be available (i.e. its crashed) and a BDC needs to be promoted, as in the absence of a PDC, a BDC does not automatically promote itself.
