Customising the default icon of an Office Add-in for Outlook


When you install an add-in from the Office store, it will come with a predefined set of icons. Depending on your organisation's needs, you might need to change those.

More Information

The icons Outlook will display are defined in the add-in manifest, which you can extract using Fiddler.
You would need to locate the GetAppManifests call and find the correct add-in manifest by right-clicking the manifest node for each entry and selecting Send to TextWizard.

When you've found what you're looking for, copy the XML content into Notepad or any other text editor and replace the following elements with the image of your choice:

 <IconUrl DefaultValue="YOUR_IMAGE_URL_HERE<!-- for example: -->" />
<HighResolutionIconUrl DefaultValue="YOUR_IMAGE_URL_HERE<!-- for example: -->" />

<bt:Image id="icon16ReportMessage" DefaultValue="YOUR_IMAGE_URL_HERE<!-- for example: -->" />
<bt:Image id="icon32ReportMessage" DefaultValue="YOUR_IMAGE_URL_HERE<!-- for example: -->" />
<bt:Image id="icon80ReportMessage" DefaultValue="YOUR_IMAGE_URL_HERE<!-- for example: -->" />

Note: The elements in the above example are from the Report Message store add-on.

In addition, you will need to create a new guid for your add-in:

<!-- IMPORTANT! Id must be unique for your add-in, if you reuse this manifest ensure that you change this id to a new GUID. -->
<!--Version. Updates from the store only get triggered if there is a version change. -->

If you want to easily create a new guid, you can run the following command in Windows PowerShell: [Guid]::NewGuid()

The last step is to save the xml file to disk and install the add-in using the xml file.


This workaround is not supported nor recommended by Microsoft. Should you wish to continue with such a customisation you cannot get in touch with Microsoft Support and request assistance should the add-in stop working or should you experience unexpected behaviours when trying to use the add-in.

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