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.