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During the installation of the Outlook Add-in, you might receive an error message that will halt the installation :

The value of the property 'type' cannot be parsed. The error is: Could not load file or assembly 'Microsoft.Office.BusinessApplications.Fba,Version=, Culture=neutral, PublicKeyToken=71e9bc3111e9429c' or one of its dependencies. The system cannot find the file specified (C:\Program Files\Common Files\Microsoft Shared\VSTO\10.0\VSTOInstaller.exe.Config line 10).


This message indicates a problem with the installation of Visual Studio 2010 Tools for Office (VSTO), a prerequisite for the Outlook Add-in.

This error can also happens when there is a corrupt VSTO file already present in your system, possibly from another Outlook Add-in.

If this error is encountered, it is best to install VSTO separately.

Here is how to do so:

  1. Download the installation file of Visual Studio 2010 Tools for Office (Microsoft link) : vstor_redist.exe.
  2. Browse to the following location using Windows Explorer "C:\Program Files\Common Files\Microsoft Shared\VSTO\10.0" (if you use a 32-bit OS, the path will be "C:\Program Files (x86)\Common Files\Microsoft Shared\VSTO\10.0" instead).
  3. Rename the file VSTOInstaller.exe.config to VSTOInstaller.exe.config.old (adding the ".old" extension, to keep a backup copy of the file, just in case).
  4. Run the installer : vstor_redist.exe.
  5. If it fails, try to run the installer as an Administrator: right click on the vstor_redist.exe file and choose "Run as Administrator".