OK, I have added backup AD's to domain's before. Ran the domain, forest prep ... etc. etc. However, I am adding a 2008 server as a backup AD to a 2003 domain this time. The 2003 is the AD (or Domain Controller), i did all the preps on the AD on the 2003 server. Now when I go and try to add the 2008 as a AD (backup DC) it says it will not be read only and in order to add it as read only I need a 2008 DC ... does it really matter in this case if the 2008 is read only or not read only. I really don't think so, but just checking. Please do not post unless you have done this before.