Excel Add-In - ClickOnce - VSTOInstaller.exe.config file, what is it?

Question

EDIT : Looks like a Microsoft issue, see forum indicated by correct answer.

EDIT 2: I am going to stop monitoring this page, looks like the Microsoft forum is dead and I also don't work for the same company anymore.

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We have a Excel Add-in (C# / .NET 4.0) which supports Excel 2007/2010/2013 and is deployed through Excel Add-In. Today, a new client ran into problems on a single machine (other machines installed the add-in correctly). The error was:

The value of the property 'type' cannot be parsed. The error is: Could not load file or assembly 'Microsoft.Office.BusinessApplications.Fba, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c' or one of its dependancies. The system cannot find the file specified. (C:\Program Files (x86)\Common Files\Microsoft Shared\VSTO\10.0\VSTOInstaller.exe.Config line 10)

My buddy Google gave me a number of suggestions: We had the client try a repair of MS VSTO Tools for Office and a repair of Office, and had the IE cache cleared, but continued to get the same error. Finally, we tried re-naming the VSTOInstaller.exe.Config to 'hide' it from the installation and it appears to be working.

I don't believe that our Add-In or installation produces this file, and there is no dependancies on this file that I'm aware of (it appears to be related to a SharePoint assembly)

While I don't explicitly download the add-in myself (I run it through VS2013), I have a VSTOInstaller.config file (Note, not *.exe.config, as seen from client) which contains the following XML:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <system.net>
    <webRequestModules>
      <remove prefix="http:"/>
      <remove prefix="https:"/>
      <add prefix="http:"
           type="Microsoft.Office.BusinessApplications.Runtime.DeploymentAction.HttpFbaRequestCreator,Microsoft.Office.BusinessApplications.Runtime,Version=14.0.0.0,Culture=neutral,PublicKeyToken=71e9bce111e9429c" />
      <add prefix="https:"
           type="Microsoft.Office.BusinessApplications.Runtime.DeploymentAction.HttpFbaRequestCreator,Microsoft.Office.BusinessApplications.Runtime,Version=14.0.0.0,Culture=neutral,PublicKeyToken=71e9bce111e9429c" />
    </webRequestModules>
  </system.net>
</configuration>

In order to get a better idea of why this client is getting the specified error, I'm looking into

1. Where this file could have come from.
2. How does it affect the installation.
3. Any other comments or general tips related to the exception, or better yet, how to avoid it altogether.

Answer 1

Just try to rename the VSTOInstaller.exe.Config to VSTOInstaller.exe.Config.old and then run the setup