The Exchange team is aware of issues with the Windows Operating System updates published July 10th, 2018 causing Exchange to not function correctly. The Windows servicing team has advised us that they will be releasing updates to the affected packages. We encourage Exchange customers to delay applying the July 10th updates, including the security updates released on the same date, on to an Exchange server until the updated packages are available.
Update: July 17th
We wanted to provide you an update on this issue.
The issue has been resolved and new updates will be available through Windows Update for all operating systems by end of day July 17th (PDT). The Exchange Team recommends that customers use Windows Update or update the catalogs on their own SUS servers to ensure the latest version of the update is available for installation on your Exchange Servers. Doing so will avoid any possible disruption to the MSExchangeTransport service which may have been impacted by the July 10th update.
Update: July 18th
The Windows team has informed us a delay occurred in the release of some packages. Updated packages are now available via the regular release channels: Windows Update, Catalogue, WSUS. These updates should be applied based upon the operating system version you are using with Exchange Server. When using Windows Update to apply an update, you will need to initiate a manual request in the Windows UI to find and download updates.
For Windows 2016, the update will be applied as a replacement to the package delivered on July 10th. Customers running Exchange on Windows Server 2016 should ensure that the latest operating system updates are applied. These updates are available now and can be applied to a production system regardless of previous updates installed.
For operating systems prior to Windows 2016, the update will be applied as an additional update to the updates released on July 10th. This means you must apply the July 10th update and then may need to execute Windows Update again to receive the additional update to fully resolve the issue. The updates for these operating systems should be fully published to all geographies on Windows Update by end of day July 18th (PDT).
The table below outlines the impacted KB for each operating system and the associated KB which must be applied to resolve the issue. In the case where there are multiple updates listed for an operating system, only one of the updates should be required. The presence of two updates is indicative of whether a rollup or individual security update is being used to update the operating system.
Update which must be applied
Windows Server 2016
Windows Server 2012R2
Windows Server 2012
Windows Server 2008R2 SP1
Windows Server 2008
The updates in question apply to the operating system and address an issue which causes the Exchange Transport service, responsible for delivering mail, to stop functioning. This condition is unrelated to the .NET changes which were published on the same date. The Exchange team continues to encourage customers to make use of Windows Update or SUS to ensure that the operating systems updates are applied correctly to an Exchange Server.
Update: August 31
One more update as we had some questions on this: we are currently not aware of any related issues with August 2018 updates.
The Exchange Team