Adprep must wait for replication to complete. Status/Consequence Forest-wide information has already been updated on the ...

Adprep must wait for replication to complete.
[Status/Consequence]
Forest-wide information has already been updated on the Active Directory Domain Controller %1, which holds the schema operations master role.
[User Action]
Wait for the replication process to complete before continuing to upgrade this Active Directory Domain, or run adprep again with the /forceReplicate switch.