Office Online Server Showing “Unhealthy” Status

*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=, Culture=neutral, PublicKeyToken=xxxxxxxxxxx' or one of its dependencies. The system cannot find the file specified. File name: 'Newtonsoft.Json, Version=
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 (

As with previous health related issues, this will not affect the OOS functionality.

*Update 10/26/16*

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="" xmlns:xsi="">
<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 :




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.

Comments (16)

  1. Mike Weaver says:

    I fix the issue I think. I was getting error with performance monitoring. so I dud the following: Run CMD as an Admin
    01. cd %SYSTEMROOT%\System32\wben
    02. regsvr32.exe WmiApRpl.dlll

  2. scks says:

    Any tentative date when the fix will be available for this issue?

  3. scks says:

    Sorry, didn’t notice the update.
    We have to uninstall the previous version of office online server and then install November 2016 released version to resolve this health issue? are there any kind of updates released that can be used to fix the issue without uninstalling current version?

    BR, Sarath

  4. Marian says:

    Pls fix the provided links, it points to ARM version of VC Redistributable.

    1. Thank You, I have fixed the link.

  5. Akhoon Rafiq says:

    Do we have any fix for this issue? I am stuck with the same error please update

  6. Akhoon Rafiq says:

    Ok , i did work hard on it and finally i got the fix for this. Thanks

  7. Akhoon Rafiq says:

    Install Visual C++ Redistributable for Visual Studio 2013 both 32 bit and 64 bit after that wait for 15 minutes, health status would turn to HEALTHY.

  8. I Installed OOS November 2016 release but still getting the Unhealthy Status, I installed Visual C++ Redistributable for Visual Studio 2013 both 32 bit and 64 bit but no luck. here is one of th error…UlsControllerWatchdog reported status for UlsController in category ‘Verify Trace Logging’. Reported status: Trace string is found but the format is not correct in C:\ProgramData\Microsoft\OfficeWebApps\Data\Logs\ULS.

    1. This is one of the errors that should have been addressed with the November release. You uninstalled the previous version and used the new installer from the November release correct?

    2. RicardoCDS says:

      I cannot say for sure, but can you verify your Regional settings. We have a OOS Farm deployed and it was also in an Unhealthy state. One of the event log errors was also “…but the format is not correct..”. I did set both OOS Servers Regional settings – Formats to match English US + the language for non-Unicode programs set English US. I also did run the copy current settings to Welcome screen and system accounts in the Administrative section. I did reboot both machines and they very Healhty afterwards. It’s just my assumption that the Regional settings are related, but I cannot say for sure.

    3. Akhoon Rafiq says:

      Its known issue even it though the status is unhealthy you will still be able to share the PPT

  9. Gustav says:

    We have installed the new Version of Online Server 2016 and get this error: The following fields has the wrong format or content: [ Timestamp ]. Because of that the status is unhealthy, but the OOS works without any problems.
    Is it necesserary to install the language Pack?

  10. Pavel says:

    I can confirm that changing the regional setting to English-US has solved my problem with the unhealthy OOS farm, as RicardoCDS writes.

  11. I have Newest April 2017 OOS installed and I am still getting this error. My OOS is not able to show any document from my SharePoint Farm.

    1. The health status showing unhealthy does not necessarily mean that that the OOS farm is not working correctly as this can show unhealthy for many different reasons. In your case I would troubleshoot the functionality of the OOS farm before worrying about the health status.

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