MFA Security Issues

How to Stop the Certificate Selection Dialog in Excel Add-ins

Maira Mehtab Sep 28, 2026 869 views

Question details

The user wants to prevent the Select a certificate for Authentication dialog from appearing repeatedly in React-based Excel add-ins deployed across QA, UAT, and production environments.

Product: Microsoft Excel Add-ins
Device & OS: not provided
Scenario: Developing and deploying React-based Excel add-ins where users are repeatedly interrupted by client-certificate authentication prompts.
Observed behavior: The Select a certificate for Authentication dialog repeatedly pops up, interrupting the workflow across multiple environments.

Before you start

Before modifying your authentication flow, ensure you have administrative access to your Microsoft Entra ID tenant and the appropriate permissions to update your Excel add-in manifest.

Solution 1Recommended

Implement Token-Based Authentication (SSO)

Replace client-certificate authentication with token-based authentication to eliminate repetitive certificate prompts entirely.

Token-based authentication provides a seamless user experience by avoiding manual certificate selection dialogs. By implementing the Office SSO API, the add-in can authenticate users silently in the background.

Configure Microsoft Entra ID

Register your Excel add-in application in the Azure Portal under Microsoft Entra ID to enable single sign-on (SSO) capabilities.

Update the Add-in Manifest

Add the WebApplicationInfo section and required resource properties to your add-in's XML manifest file to authorize the application.

Implement the Office SSO API

Use the OfficeRuntime.auth.getAccessToken() method in your React codebase to silently request authentication tokens without prompting the user.

Seamless Authentication: Using OAuth 2.0 or Microsoft Entra ID single sign-on is the Microsoft-recommended approach for modern Office Add-in authentication.

Solution 2

Automate Client Certificate Deployment

If your organization strictly requires client-certificate authentication, configure endpoints to trust certificates automatically without manual user intervention.

Free Microsoft Office alternative

Need a simpler spreadsheet solution? Try WPS Office

If managing complex authentication flows, enterprise add-ins, and recurring certificate prompts in Microsoft Excel becomes overwhelming, consider switching to WPS Office. It provides a highly compatible spreadsheet editor without the heavy administrative overhead.

1. Download WPS Office: Visit the official WPS website and download the free installer for your operating system.
2. Install the Software: Run the installer and follow the quick setup wizard to complete the installation.
3. Open Your Spreadsheets: Launch WPS Spreadsheets and open your existing .xlsx files directly to start working.

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microsoft office alternative - wps office

Frequently Asked Questions

Why does the certificate selection dialog keep appearing in my Excel add-in?

This occurs when the add-in relies on client-certificate authentication and the embedded browser engine (such as Edge WebView2) cannot automatically select a trusted certificate, forcing a manual prompt for the user.

Can I use the Office SSO API in a React-based Excel add-in?

Yes, you can implement the Office SSO API using OfficeRuntime.auth.getAccessToken() within your React components to silently authenticate users via Microsoft Entra ID without triggering certificate prompts.

How do I auto-select certificates in Edge WebView2?

You can configure the AutoSelectCertificateForUrls enterprise policy in Windows to automatically choose the correct client certificate for your add-in's domain, effectively bypassing the manual selection dialog.

Microsoft Office Security Issues