Exchange 2013 Cumulative Update - This Account is not...

Exchange 2013 CU10

When trying to install Exchange 2013 Cumulative Update 10(CU10) we received an error reporting that the installing users account is not a member of schema admins, other elevated groups, that AD doesn't exist, or that the forest level is not 2003 or later. 

We verified that we had proper permissions on the account, AD exists ;-), and that the forest level was at 2012. So none of these applied... :-(

Exact errors from the ExchangeSetup.txt log file

[1] Failed [Rule:SchemaUpdateRequired] [Message:The Active Directory schema isn't up-to-date, and this user account isn't a member of the 'Schema Admins' and/or 'Enterprise Admins' groups.]

[1] Failed [Rule:AdInitErrorRule] [Message:Setup encountered a problem while validating the state of Active Directory: Exchange organization-level objects have not been created, and setup cannot create them because the local computer is not in the same domain and site as the schema master.  Run setup with the /prepareAD parameter on a computer in the domain YourDomain and site YourDomainsSiteName, and wait for replication to complete.  See the Exchange setup log for more information on this error.]

[1] Failed [Rule:ForestLevelNotWin2003Native] [Message:The forest functional level of the current Active Directory forest is not Windows Server 2003 native or later. To install Exchange Server 2013, the forest functional level must be at least Windows Server 2003 native.]

[1] Failed [Rule:CannotAccessAD] [Message:Either Active Directory doesn't exist, or it can't be contacted.]

Our Remedy

Depending on the current state of your Schema and what updates you might have applied Active Directory may need to be prepped before the cumulative update may be installed. Which was the case for us but it wouldn't let us update the schema from any server except the schema master.

1. Find your schema master. To find the schema master open an elevated command prompt and run: netdom query fsmo
2. Login to the schema master server, and copy and extract the CU to a local drive
3. Open an elevated command prompt to the location of the CU (this will not work from Powershell) and run: .\setup.exe /Preparead /iacceptexchangeserverlicenseterms
4. Give it a couple minutes to complete preparing AD and you'll be good to go to retry the update on your Exchange server/s
5. Run the CU setup.exe from the Exchange 2013 server/s and await completion.