Error MSB3482: An error occurred while signing: Failed to sign

Question

I have .pfx certificate which is self signed. I've signed the ClickOnce manifest of my VSTO (Excel Add-In project type in Visual Studio) project. Recently we have migrated the application from .Net 3.5 to 4.5 and Office 2007 to 2010 since then project (that used to work) and now it gives me an error:

An error occurred while signing: Unknown error "-2147012894"
SignTool Error: An unexpected internal error has occurred
The certificate is perfectly valid and not expired

Anyone had this kind of error before? Any suggestions?

Answer 1

Try creating a new certificate.

Look at the "Signing" section under the project's properties.

In my case, my MSB3482 error occurred because my certificate had indeed expired. I clicked the button called "Create Test Certificate" and I was able to build and run again. (At least for another year)