Getting security warning Unknown publisher issue while install the .exe or update the application using click once

Question

Dear Support,

I have created a Windows application using WPF and deployed it to a server location using Click-Once. It was properly digitally signed and used by everyone in the organization. However, recently we have started getting the "Unknown Publisher" security warning and "Publisher can't be verified" message whenever a new version is published and users update to the latest version.

I checked the digital signature and confirmed that it has not expired. We haven't changed any configuration settings either. This warning issue has only started appearing recently.

I suspect this could be related to a recent Microsoft OS update, but I'm not sure.

I have tried all the recommended solutions available in various forums, and we have already followed them. Can anyone please provide guidance on how to resolve this issue?

Thanks,

Bharathi.

Answer 1

Hi,@Bharathiraja Kethappan. Welcome to Microsoft Q&A. 

Open certmgr.msc (C:\Windows\System32), add your certificate in Trusted Root Certification Authorities->Certificates to make it a trusted certificate.

 

A simple example: When publishing with ClickOnce, you create a certificate by Create test certificate

 

The certificate will be stored in the Personal->Certificates location (you could confirm it by the creation time).

 

At this point you could select it and paste it into Trusted Root Certification Authorities->Certificates by right clicking->Copy.

 

Now you will not get the Unknown Publisher error when installing the application.

 

Of course, there are other ways to add trusted certificates (commands, X509Store) that you could refer to:

Add trusted publisher to client box (ClickOnce) - Visual Studio (Windows) | Microsoft Learn

X509Store Class (System.Security.Cryptography.X509Certificates) | Microsoft Learn

 

Finally, you should ensure that the certificate you update your application with is consistent with the locally stored trusted certificates.

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