We have a test environment which was 2008R2 AD.  We properly went through the migration path and are currently at 2012R2 Active Directory functional level.

I'm installing Exchange 2013 with Sp1 into the domain.  I have successfully prepared the domain as outlined on technet, and verified its success with the logs and looking in ADSI edit.  No errors.  All seems to have ran correctly.

When I attempt to install the first exchange mailbox server, the Readiness check fails saying "the local domain needs to be prepared using Setup /PrepareDomain before server roles can be installed"...  1 forest, 1 root domain, 1 child domain.  The account I'm using is a member of Schema Admins, Enterprise Admins, Domain admins etc.  

Has anyone else come across this or have any suggestions?

try setup /preparealldomains

Also, is there any reason you are going with SP1(this is CU4 with a fancy marketing name) and not a newer CU release (like 7 or 8) MSFT only supports 2 CU's back

Can I do a new install with the latest RU?  Yes, I've done setup /prepareall domains.  

Yes.  Each CU contains a full installation of Exchange 2013.

Thanks!  I'll use that install from here on out.  I downloaded CU7, put the code on one of the root DC's, ran the Prepareschema, Prepareactivedirectory and Preparealldomains.  All completed successfully...I also ran repadmin /syncall after each one.

I then went to the server which I'm installing exchange on (2012R2 domain member), run the setup as administrator (the domain account I'm logged in as has all the necessary rights) and got the same "issue" on the Readiness check..."Error:  The local domain needs to be prepared using Setup /PrepareDomain before server roles can be installed.  

So...I logged onto on of the DC's in the child domain and ran the preparedomain.  Attempted Exchange install again...same thing.

Hi randkflem,

Thank you for your question.

Are there multiple DCs in child domain?

Please make sure all DCs on child domain could be replicated. We could make sure Exchange server could connect to DC without any problems(include DNS resolution).

If the issue persist, we could restart the DC and Exchange server on child domain to check if the issue persist.

If there are any questions regarding this issue, please be free to let me know. 

Best Regard,

Jim