An important update is now available to resolve issues customers are currently experiencing when using the Hybrid Configuration Wizard (HCW) to create a new or manage an existing hybrid deployment with Microsoft Exchange Server 2013.
If you currently have an Exchange 2013-based hybrid deployment configured, you will not notice any issues unless you rerun the HCW as part of updating or managing your existing hybrid features. Unless you need to reconfigure your hybrid deployment, you can simply wait for the next update of Exchange Server 2013 (Cumulative Update 6) to correct this issue with the HCW.
For Exchange 2013 organizations creating new or managing an existing hybrid configuration with the HCW, the following HCW error message indicates you are experiencing the issue this update addresses:
Subtask CheckPrereqs execution failed: Check Tenant Prerequisites Deserialization fails due to one SerializationException: Microsoft.Exchange.Compliance.Serialization.Formatters.BlockedTypeException: The type to be (de)serialized is not allowed: Microsoft.Exchange.Data.Directory.DirectoryBackendType
Once the Interim Update (IU) is applied, customers can successfully run the HCW and complete configuring a hybrid deployment with Office 365.