*UPDATE 12/5 2017*
We had a previous known issue below that always made the OOS server show an unhealthy status, this was fixed in the 11/17/2016 release of OOS.
We are now seeing a new issue in the November 2017 CU for Office Online Server. This new issue is causing the same unhealthy status but with different errors. We will see errors similar to the following in the event viewer:
An exception occurred during a watchdog callback for Rtc2Watchdog. System.IO.FileNotFoundException: Could not load file or assembly 'Newtonsoft.Json, Version=188.8.131.52, Culture=neutral, PublicKeyToken=xxxxxxxxxxx' or one of its dependencies. The system cannot find the file specified. File name: 'Newtonsoft.Json, Version=184.108.40.206
Unhandled exception is being reported by SI platform. Microsoft.Office.ServiceInfrastructure.Runtime.Settings.SettingNotDefinedException: Cluster specific setting 'MonitoringAgentUlsFileWriterEnabled' not defined or of the wrong type.
Microsoft is currently investigating the issue, and I will update this page after it is corrected.
More detailed information can be found here (https://thesharepointfarm.com/2017/11/office-online-server-november-2017-errors)
As with previous health related issues, this will not affect the OOS functionality.
The new version of Office Online Server released on 11/17/2016 has health fixes in place.
You may still get a OneNoteMerge health error in the event log like this:
<?xml version="1.0" encoding="utf-16"?>
<HealthReport xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<HealthMessage>WebOneNoteWatchdog reported status for OneNoteMerge in category 'Ping'. Reported status: OneNote Merge Ping test failed. OneNoteMerge.exe not available to execute merge</HealthMessage>
<Severity xsi:nil="true" />
If you are then you will need to install the X64 version of the Visual Studio Runtime : https://www.microsoft.com/en-us/download/details.aspx?id=40784
Office Online Server (OOS) shows that the servers are in a Unhealthy status. This status will even occur on a new farm with default settings.
The OOS product team has identified a few different health checks that are failing and causing the status message to show unhealthy.
The OOS product team is in the process of correcting the health checks in an upcoming patch for OOS. We do not have a timeline on when this will be released, but this blog will be updated when the patch is available.
*The healthStatus message should not be a indication of functionality of a OOS farm.