VSTO Outlook Add-In Ribbon not showing in Outlook 2007

Question

I have an Outlook add-in developed using VSTO Outlook 2010 template which has a ribbon. The ribbon xml is

<?xml version="1.0" encoding="UTF-8"?>
<customUI onLoad="Ribbon_Load" xmlns="http://schemas.microsoft.com/office/2006/01/customui">
    <ribbon>
        <tabs>
            <tab idMso="TabAddIns">
                <group id="PluginGroup" label="the Collective">
                    <button id="FolderSelector" onAction="FolderSelector_Click" screentip="Click to select forwarding folder" label="Folder Selector" showImage="false" />
                    <labelControl id="label1" label="Current Folder :" screentip="Folder which all email will be forwarded" />
                    <labelControl id="guiCurrrentChooserFolder" label="Please Select a folder" />
                </group>
            </tab>
        </tabs>
    </ribbon>
</customUI>

This ribbon shows and functions properly in Outlook 2016. However, the ribbon does not show in Outlook 2007. Is this a compatibility issue? How can I modify this xml to support Outlook 2007 as well?

Other than the UI, the functionality of the Add-In is working in both Outlook 2016 and Outlook 2007. I'm using Visual Studio 2015 to develop this.

Do you see any errors if you enable "Show Addin-in user interface errors" in Options | Advanced | Developers ? — Dmitry Streblechenko
@TonyD no this project was sort of paused as we already had an older version of the product for 2007. I don't think we will update the 2007 version anymore. — kovac

aduguid aduguid · Accepted Answer · 2018-01-16T23:24:00

You must first install the Outlook 2007 Primary Interop Assembly (PIA) in the Global Assembly Cache (GAC) before you can incorporate information from the PIA in an Outlook managed add-in. You can do so by choosing the Typical installation of Office and then adding .NET Programmability Support for Outlook.

To add .NET Programmability Support for Outlook after Outlook is installed In Control Panel, click Add or Remove Programs.

Select your installation of Office and click Change.

Select Add or Remove Features.

Click Continue.

In the Installation Options tab, click the '+' to expand the application for which you want to install the PIA.

Click the drop-down arrow adjacent to .NET Programmability Support and select Run from My Computer.

VSTO Outlook Add-In Ribbon not showing in Outlook 2007

1 Answers