SBS 2003 Install: schema mismatch/unable to contact all DCs

Posted on 2007-10-21
Last Modified: 2009-07-08
I had/have an AD domain with a SBS 2003 Server controlling it all.  The AD had two sites in it, one for the local office and another for our data canter computers.  The data center has a W2K Server as a DC so that if the VPN between our office and the data center went down, we would still be able to manage  our production web servers.  Long story short, somebody opened up an email attachment  which somehow bypassed the virus protection and infected this server.  The virus tweaked the OS and Exchange where our only solution to fixing the server was to do a fresh install on the server and start anew.   I repaired/defraged and performed integrity checks on the Exchange database and backed it up so that when the server was rebuilt we could reattach the old stores to the new server.  

Before I leveled the SBS server, I brought up a new W2K3 R2 server and promoted it to a DC and transferred all roles to it.  I started the fresh install of SBS 2003 (keeping the servers name the same) on the original server, stopping it before it did its integrated install as to make sure that it joined the current domain where it now has all the operational roles once again.

The issue is that I cannot get the SBS server to continue its install as the install fails at the check for System Requirements and returns an Unable to contact all domain controllers message.  I checked at each server to see if there was a DNS issue and there was not, all servers can resolve to each other without issue.  Starting to get desperate, I decided to demote all of the outlying DCs so I was only dealing with the SBS PDC.  When I tried to demote the W2K server in the data center and I get an error declaring "The replication operation failed because of a schema mismatch between the servers involved."  

Being of little AD knowledge (enough just to be dangerous!) my thoughts were to bring up another DC at the data center (W2K3 R2) and see if that helped the W2K DC synch up.  It doesnt& so then my thought went to forcibly demote the W2K DC  since there is a new W2K3 DC over there.  But everything I read says not to do that.  

I am at a quandary and I need help so I can continue the SBS install and get Exchange back on line.  
Question by:moatman
    LVL 95

    Accepted Solution

    I don't think I can be of much help, but your problem is probably due to the fact that you have an R2 domain controller - or had one.  R2 made schema changes and it's probably what's causing that error.  I think you'll have to completely start over and restore from backups - but I'm not sure and you might be better off to wait for/hope Jeff/TechSoEasy has some suggestions...
    LVL 74

    Assisted Solution

    by:Jeffrey Kane - TechSoEasy
    You need to update the SBS's AD Schema to Windows Server 2003 R2.  This is done by inserting the Server 2003 R2's CD2 in the SBS, switching to the cmpnents\R2\ADPREP directory and then running adprep /forestprep.

    LVL 48

    Assisted Solution

    hmmm your schema updates only apply when adding a new new schema version into an older domain.....schema mods are always backwards compatible, meaning that even at an R2 schema level, you can pull a 2k DC in without problems, so i am highly dubious that this is a schema level problem - i could be wrong though

    Which server currently holds the roles - not being an SBS person, i didnt think you could transfer roles??? Jeff??

    we need to clarify which server is the main one at the moment and then we can deal with the problemtatic additional DC's easily enough

    LVL 74

    Expert Comment

    by:Jeffrey Kane - TechSoEasy
    Well, the process that he's going through is what's detailed in

    I always recommend against using this method for installing an SBS because it inherintly has tons of problems if you don't follow it EXACTLY, and I've never seen it used when there are multiple sites configured in the domain.

    In rereading the question though, I'm now thinking that the "NOTE" listed in step 7e of that KB article may be the problem.


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