Since the release of Microsoft Exchange Server 2013 Service Pack 1 (SP1), Microsoft has become aware of an issue that affects some customers who use transport agents that are provided by third-party OEMs. For more information about this issue and a supported fix, see the following Microsoft Knowledge base article:
2938053 Third-party transport agents cannot be loaded correctly in Exchange Server 2013
Microsoft has released Microsoft Exchange Server 2013 Service Pack 1 (SP1). This service pack is dated February 25, 2014. This article describes the following information about the service pack:
The issues that the service pack resolves
How to obtain the service pack
The prerequisites for installing the service pack
For more information about the coexistence of Exchange 2013 and earlier versions of Exchange Server in the same environment, go to the following Microsoft website:
The setup process for Exchange Server 2013 will identify any missing prerequisites.
After you install a service pack, you must restart the computer so that changes can be made to the registry and operating system.
After you install a new service pack for Exchange 2013, you cannot uninstall the service pack to revert to an earlier version of Exchange 2013. If you uninstall the service pack, Exchange 2013 is removed from the server.