ClickOnce - Cannot publish because a project failed to build

Question

When I try to publish my (WPF, C#) application, I get these errors:
Cannot publish because a project failed to build.
Could not find file \'obj\\x86\\Debug

Answer 1

I just ran into the problem today. In my particular case, it was caused by Microsoft Windows Update, Microsoft Security Advisory 2661254 (concerning minimum certificate key length).

I uninstalled that update and publish began working as it always had. This is only a temporary work around and means you should probably regenerate your keys/certificates.