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Outlook Ribbon Add-in Manifest Issues

Sergio Jacomella 0 Reputation points
2025-08-05T07:53:52.55+00:00

An add-in has been successfully created that works as expected within the Calendar context. However, there is an attempt to create a separate add-in that should always be accessible from the main Ribbon in Outlook, independently of whether the user is in Mail, Calendar, or any other module.

Despite several attempts and manifest variations, the following issues are being encountered:

  • In some cases, the add-in cannot be installed at all (using sideload or centralized deployment).
  • In other cases, the installation completes successfully, but the add-in does not appear anywhere in Outlook — not in Mail, not in Calendar, and not in the Home tab.

The same manifest passes XML validation and appears to follow the official documentation for Ribbon-based command add-ins.

The goal is to provide a simple Ribbon button (e.g. in the Mail or Calendar Home tab) that opens a specific web application in a task pane, regardless of the current view or selection in Outlook.

Assistance is needed to:

  • Confirm what conditions must be met for the add-in to appear on the Ribbon.
  • Point to any platform limitations, known issues, or hidden constraints that may explain why the add-in fails to appear.
Developer technologies | XAML
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  1. Deleted

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  2. Surya Amrutha Vaishnavi Lanka (INFOSYS LIMITED) 335 Reputation points Microsoft External Staff
    2025-08-22T12:34:37.3466667+00:00
    1. Check Outlook version

    Make sure you’re using Outlook latest version (desktop/web).Older versions don’t support ribbon add-ins.

    1. Add correct ExtensionPoints:

    For Mail - MessageReadCommandSurface

    For Mail compose - MessageComposeCommandSurface

    For Calendar - AppointmentAttendeeCommandSurface and

    1. Add requirements

    In manifest, include:

    <Requirements>

      <Sets DefaultMinVersion="1.5">

        <Set Name="Mailbox" MinVersion="1.5"/>

      </Sets>

    </Requirements>

    1. Remove restrictions

    If you used conditions like <Rule xsi:type="ItemIs"...> or <Rule xsi:type="ItemHasAttachment">, remove them to test. This ensures the button always shows.

    1. Clear cache & redeploy 

    %LOCALAPPDATA%\Microsoft\Office\16.0\Wef\

    Then sideload or redeploy the add-in again.

    1. Check in Outlook

    Go to Outlook - Options - Add-ins

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