OS Patching Break SharePoint OWA Servers

Hi @Nguyen, Tee

How did you do OS patching?
I find two articles "Apply software updates to Office Web Apps Server" and "Apply software updates to Office Online Server".
As said in them, "Applying Office Web Apps Server/Office Online Server updates by using the automatic updates process isn't supported with Office Web Apps Server/Office Online Server. This is because updates to an Office Web Apps Server/Office Online Server must be applied in a specific way, as described in this article. If Office Web Apps Server/Office Online Server updates are applied automatically, users may be unable to view or edit documents in Office Web Apps/Office Online Server. If this happens, you have to rebuild your Office Web Apps Server farm. To rebuild a farm, you must remove the Office Web Apps Server from the farm by using Remove-OfficeWebAppsMachine, uninstall Office Web Apps Server/Office Online Server by using Add or remove programs, and then reinstall Office Web Apps Server by following the steps that are described in Deploy Office Web Apps Server/Deploy Office Online Server. After you have reinstalled, apply the update by following the steps that are described in this article."

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