Assume that you enable the Windows "Failover cluster" feature on an Exchange Server 2013 server, and the server is not a member of a database availability group (DAG). In this situation, you cannot create a mailbox database on the Exchange server. Additionally, you receive the following error message:
An inconsistency in the Active Directory was detected: Database 'Database name' is expected to be in a database availability group but the value for its MasterServerOrAvailabilityGroup property ('ServerName') is not valid.
This issue occurs because the Exchange server is considered to be a member of a DAG incorrectly when it has the "failover cluster" feature enabled.
To resolve this issue, install Exchange Server 2013 Service Pack 1:
2926248 Description of Exchange Server 2013 Service Pack 1
To work around this issue, remove the "Failover cluster" feature on an Exchange Server 2013 server.