GlobalSCAPE Knowledge Base

Installing the Mail Express Add-in Prerequisites

Karla Marsh
Mail Express


  • Mail Express, v3.3.2 and later


The Mail Express Outlook Add-in has several dependencies which the help guide details and provides installation information for. This KB article describes special case scenarios to consider that supplement the information in the help guide.

Microsoft Outlook 2013 Primary Interop Assembly

The Microsoft Office 2013 Primary Interop Assemblies Redistributable (PIA) is not yet available to download from Microsoft’s web site. This means that the Outlook 2013 Add-in Bootstrapper will not install this dependency as there is no installation package for the PIA yet. The PIA is a dependency that the add-in requires in order to function. By default, when Microsoft Office is installed, the Outlook PIA is also installed if .NET was installed beforehand on the system. If needed, the PIA can be installed using the Microsoft Office Installer.

The steps to install the PIA after Microsoft Outlook is installed are as follows:

  • From the Windows Control Panel choose “Programs and Features.”  
  • Select “Microsoft Office 2013” from the list of installed programs.  
  • Press the “Change” button, select the “Add or Remove Features” radio button, and then press the “Continue” button.  
  • Expand the “Microsoft Outlook” node and then choose the “Run from My Computer” menu option for the “.NET Programmability Support” feature and finally press the “Continue” button.

A similar approach can be taken to install the PIA when installing Outlook for the first time.


For versions of Outlook prior to Outlook 2013, the PIA can be downloaded from Microsoft’s web site or can be installed via the Mail Express Add-in Bootstrapper. Please consult the Mail Express help guide for more information.

Last Modified: Last Year
Last Modified By: kmarsh
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