Microsoft Warns of Hybrid Exchange 2013 Glitch
Microsoft issued a warning to IT organizations running so-called "hybrid" messaging environments that combine Exchange Server 2013 and Exchange Online.
The July 30 announcement explains that organizations should hold off on using the Hybrid Configuration Wizard for creating new hybrid Exchange environments or updating existing ones, if organizations use, or are planning to use, a combination of Exchange Server 2013 and Exchange Online. It's not clear from the announcement or Microsoft's support article what problems organizations face, but it's bad enough that Microsoft has created an "Interim Update" for organizations with the problem.
The problem manifests via following error message after using the Hybrid Configuration Wizard:
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
Microsoft is encouraging organizations with this problem, or those who plan to update their environments using the Hybrid Configuration Wizard, to contact its technical support, as described at this page. That's how organizations can get the Interim Update, which isn't otherwise available online.
Organizations should only install the Interim Update if they have Exchange Server 2013 Service Pack 1 or Cumulative Update 5 already in place, Microsoft's announcement warned.
The problem will be more broadly addressed when Microsoft rolls out Cumulative Update 6 for Exchange Server 2013. Microsoft releases its cumulative updates on a quarterly basis. Consequently, it may be aiming to deliver CU6 either this month or the next. Its last release, CU5, was available in late May.
Microsoft's announcement claims that organizations installing the Interim Update won't have to uninstall it first when CU6 arrives. Apparently, that's a change in practice for Interim Updates that's been in effect since CU3:
The interim update does NOT need to be uninstalled. We allow later CU's to install over Interim Updates and Security Updates directly as of CU3.
The Hybrid Configuration Wizard problem only affects Exchange Server 2013. It doesn't affect earlier Exchange Server versions.
Avoiding the wizard and resorting to manual configuration isn't an option, according to Microsoft, since doing so can result in "unsupported" states.
Kurt Mackie is senior news producer for the 1105 Enterprise Computing Group.