Perform AD Schema and Domain Preparation for Exchange 2013 CU10 using the following step-by-step instructions:
1) If you haven’t already, download the latest version of Exchange 2013.
2) Next, verify AD health by running DCDIAG and REPADMIN /SYNCALL from a run-as-administrator command prompt on your DC’s.
3) Copy the download to an easily accessible folder on one of your Domain Controllers or Exchange servers (for example C:\Exch2013CU10\download). Run the downloaded file in order to extract the installation files, extract them to c:\Exch2013CU10
4) open a command prompt as administrator on the DC and prepare the AD schema using the following command from a ‘run-as-administrator’ command prompt:
setup.exe /PrepareSchema /IAcceptExchangeServerLicenseTerms
Note: your account must be a member of Schema Admins
5) Once the schema upgrade is complete, run ‘repadmin /showreps’ from the command prompt to make sure AD replication has completed and any schema mismatch errors have gone away (they will eventually go away on their own). I also recommend running DCDIAG again to make sure it passes before moving on.
6) Prepare AD by running the following command from a ‘run-as-administrator’ command prompt:
setup.exe /PrepareAD /IAcceptExchangeServerLicenseTerms