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How to find the issue for this Office.js addin error after updating?

Sebastian Vasile 6 Reputation points
2025-12-02T07:39:24.1+00:00

Hi,

After updating our Office.js add-in, several customers have reported encountering this error. The add-in was functioning properly prior to the update. The current work-around is for the customers to delete the WEF folder. After this, the add-in will open correctly. What would be the recommended approach to find the issue and fix it?

image-20251013-162535

Microsoft 365 and Office | Development | Office JavaScript API
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  1. Dora-T 8,265 Reputation points Microsoft External Staff Moderator
    2025-12-02T11:19:45.0766667+00:00

    Hi @Sebastian Vasile

    Thank you for reaching out to the Microsoft Q&A forum. 

    Based on your description, we understand that the add-in only fails after the update, and deleting the WEF cache allows it to load normally again. If clearing that folder resolves the issue, it may indicate that Excel was still loading an older cached file from the previous version of your add-in. 

    If you would like to explore this further, you may consider trying the Microsoft Edge developer tools to see whether they offer any additional clues during the add-in’s loading process. You can refer to this article for more information: Debug add-ins using developer tools for Microsoft Edge WebView2 - Office Add-ins | Microsoft Learn 

    Additionally, to help you reach your goal more effectively, you may also consider posting a thread on the Issues · OfficeDev/office-js · GitHub platform. It’s a great place for deeper technical discussions and connecting with developers who work directly with Office.js. If you’re able to gather any additional details or observations while debugging, including that information in your GitHub post may help the community provide more targeted guidance. 

    If the available tools and community resources do not provide the information you need and you require a deeper investigation, you might consider contacting Microsoft Unified Support for further assistance. You can find more information and explore this option at the following link: Microsoft Unified Overview | Microsoft Unified  

    Please understand that as moderators in this community, we don’t have access to your environment or internal systems, so we can only provide general recommendations based on publicly available documentation. We suggested these options to help you receive faster and more effective assistance.

    Thank you again for your understanding.

    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

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