SharePoint 2016 On-Prem ::: Error within Word and Excel Online

Hi All,


Today I'm closing this case opened last month at Microsoft.

The issue is that on SharePoint 2016 On-Prem, it is no more possible to open any excel nor word file in the Word/Excel Online, or to have a preview of the document.

This is the error exemple that we were experiencing:

After several hours, passed with Microsoft engineer, lot of test and logs, we came to the fact that Office Web App must be reinstalled with the latest version.

And today, I was executing the latest Action Plan (A.P) proposed by the Microsoft Engineer: cleaning the Config Cache in SharePoint 2016.

Before going further, the A.P must be executed on each servers in your Farm, otherwise, you will be facing with a nice correlation ID with this message: "An update conflict..."

Below is a summary of the issue:

Scope:
You are using SharePoint Server 2016 OnPremise and lately you noticed that the users cannot open the Office files in the browser anymore.

Also the preview does not work as expected.

To be more specific:

1. The user john.doe@contoso.com navigates to https://shp.contoso.com/sites/TeamSite01/_layouts/15/start.aspx#/MyDoc/Forms/Default.aspx and selects the Word file called “Migration Doc-01.docx
2. By opening the file in Word Online, the following message appears:

Server Error in ‘/x’ Application.
Runtime Error

Description: An application error occurred on the server. The current customer error settings for this application prevent the details of the application from being viewed remotely (for security reasons). It could, however, be viewed by browsers running on the local server machine.
Details: To enable the details of this specific error message to be viewable on remote machines, please create a <customErrors> tag within a “web.config” configuration file located in the root directory of the current web application. This <customErrors> tag should then have its “mode” attribute set to “Off”

<!—Web.Config Configuration File -->
  <configuration>
<system.web>
<customErrors mode=”Off”/>
</system.web>
</configuration>”

Notes: The current error page you are seeing can be replaced by a custom error page by modyfing the “defaultRedirect” attribute of the application’s <customErrors> configuration tag to point to a custom error page URL.

<!—Web.Config Configuration File -->

<configuration>
<system.web>
<customErrors mode=”RemoteOnly” defaultRedirect=”mycustompage.htm”/>
</system.web>
</configuration>”

Action Plan:
1 - Delete the configuration cache, on EACH servers in your Farm,  using the information from this article : https://sharepointfordummies.blogspot.com/2019/01/an-update-conflict-has-occurred-and-you.html

I've used the PowerShell script after verifying that the cache was in the correct location
(URL : to check ::: http://luisevalencia.com/2016/09/28/how-to-delete-the-sharepoint-configuration-cache-with-powershell/)

     - Stop "SharePoint Timer Service" (SPTimerV4)
     - Find folder with cache.ini and .xml
        Location on SharePoint 2016 : C:\ProgramData\Microsoft\SharePoint\Config
        Create a backup folder, and move in all the .xml
        Copy the cache.ini into the backup folder
        Edit the cache.ini file, then replace all it's content by '1' + save
      - Do this previous procedure on each server in your Farm
      - Start SPTimerV4 on each servers of your Farm

2 - Run this command Update-SPWOPIProofKey  in PowerShell, from each server in your Farm
3 - Start the timer job WOPI Discovery Synchronization from Central Administration Console : as I have 2 WFE servers, I've executed both WOPI timer jobs
4 - Test the Preview and opening online your document:

This procedure will also be working with SharePoint 2010 and 2013.
Only check the path where the config folder of SharePoint is located, and adapt into your PowerShell Script.
In 2016, it is located at: C:\ProgramData\Microsoft\SharePoint\Config

Voilà,

That’s all Folks !!!