Exchange Server 2019 Public Preview

Thanks for asking this question. There is a common misconception that Server Core does not include a Graphical User Interface (GUI). It does. Server Core removes the Explorer shell and the UI extensions. That also means that MMC is not installed because it depends on Explorer Shell. GUI based Windows applications which don't depend on Explorer or MMC continue to function normally on Server Core but may look a little different, e.g. Font usage. Even the graphical Exchange Server setup wizard runs normally on Server Core for example. What we tend to see is that the installer for some applications doesn't function normally but the underlying application works normally. In those instances, installing the application using a “quiet mode” supported by the installer is often an available workaround. Our own Unified Communications Managed API (UCMA) is an example where the previously released installer doesn’t work correctly on Server Core but the underlying functionality works fine. This is why we have created a Server Core compliant redistribution package for this and placed it in the Exchange Server 2019 .ISO. If an application installer does not work correctly, we would expect ISV's to make use of an installer that is compliant with Server Core. If the application requires Explorer or MMC, then additional work will be required by the ISV. Installing and running the management experience for these applications on a machine with the full Desktop Experience is also an option.

That being said, Windows Server 2019 Server Core will include an optional Feature On Demand (FOD) component for Application Compatibility. This is intended to assist the Windows ecosystem in their product transition to support Server Core. It will install a supported version of MMC, as well as other components, which run on Server Core. The Exchange Team will not support use of the AppCompat FOD on servers where Exchange Server is installed. This is intended to be a transitional technology only and we have worked closely with Windows over the past two years to support Server Core natively in this release. The Server Core development team is aware of our plans in this regard and has expressed support for our approach.

We believe that the transition to Server Core as the preferred operating system for Exchange Server is a journey that will improve over time as the ecosystem adapts to this change. It is one that will result in more secure servers by removing functionality not required by Exchange Server and be worth the effort.