Solving Visual Studio error - The "SignFile" task was not given a value for the required parameter "CertificateThumbprint"

A few possible reasons for this one:

1. Your cert may no longer be in the certificate store - perhaps because you reinstalled windows, or because you have moved to a new machine.
2. You have setup signing under "Signing" settings in your project properties, but haven't generated the certificate using "Create Test Certificate".
3. If your certificate was selected as a file, the file may have been deleted.

But whether you are using your own certificate, or the certificate was created by Visual Studio, you should have a *.pfx file in your project. Try doing the following:

1. Right click your project in the Solution Explorer and click properties.
2. Click on the Signing tab.
3. Make sure "Sign the ClickOnce manifests" is checked.
4. Clcik Create Test Certificate to generate a certificate, or choose one form a file, or your certificate store.
5. Click the "Select from File..." button, and select the *.pfx file in your project.

Hopefully, this will fix the problem.