Word Add-in Trusted publisher None

Question

We have non VSTO add-in loaded via mscoree.dll which is signed using azure sign tool with key vault certificate purchased via DigiCert. Enabled the Trusted Publisher checkbox (Trusted Publisher checkbox Image attached) . Launching word it shows the security warning (image attached). If I added this certificate as trusted publisher. It is still showing Publisher as None( image attached).

Can you please guide steps what needs to be done to show Publisher info and AddIn be trusted by default?

Thanks and Regards,

Answer 1

Hello @Rakesh Khullar

Welcome to the Microsoft Q&A Community!  

Thank you for reaching out and sharing a detailed description of your scenario. 

Based on your description, it appears your add‑in is a classic COM add‑in loaded through mscoree.dll. Microsoft is gradually guiding developers toward more modern and fully supported Office extensibility models.  

To help with that transition, I recommend reviewing Microsoft’s official guidance on evolving or upgrading existing solutions: VSTO add-in developer's guide to Office Web Add-ins - Office Add-ins | Microsoft Learn 

This article outlines recommended approaches for moving from legacy COM/VSTO models toward newer, more robust, and fully supported Office Add-in technologies. It may provide clarity on how your current architecture affects trust behavior, certificate handling, and how publisher information is surfaced within Office. 

If the issue still persists after reviewing the transition guidance and validating your add‑in’s signing and deployment steps, please note that the Q&A forum mainly focuses on general Office usage issues. For deeper engineering insights, especially regarding COM add-in loaders, trust mechanisms, and certificate requirements, I recommend posting your question in the Microsoft Tech Community, where product engineers and experienced developers can provide more targeted assistance. 

The experts there can help analyze advanced add‑in architectures and provide more specialized solutions. 

Thank you in advance for your cooperation and understanding. Let me know how it goes on your end. 

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