Question : adprep.exe taking extremely long time

I have an existing Win2k3 network that features two domians with two DCs each in one forest.  I need to install a Server 2008 DC at my hub site to support an RODC that i am planning for a remote site.  I am familiar with adprep and all of it's switches - /forestprep /domainprep /rodcprep etc.  I have started an adprep.exe /forestprep on my schema master for the root domain (the domain in which i plan to implement the RODC).  It is taking an extremely long time.  I think it has now been on the same dot for about 4 hours.  I receive the prompt that says the command has completed successfully, but the dots are still going across the screen - about 1 per hour now.  Also, the process is still active under Task Manager.  I am scared to kill it.  Should i just wait it out or should i kill the process and try again?  My domain only has about 800 users and about that many computer objects.

Answer : adprep.exe taking extremely long time

Then I suppose you might want to verify that there is activity on the Schema master still with taskmanager, or process explorer.

Did you check that inbound replication had occurred before starting?
http://technet.microsoft.com/en-us/library/cc773360%28WS.10%29.aspx