Manifest may not be valid or the file could not be opened.

Question

I know it is a very commonly faced problem. But, there is a slight difference, my WPF installs perfectly and runs on Windows 7 and Windows 8 OSes. But, when tried to install

Answer 1

I was able to solve my issue by removing the signing of the manifest.
If you right-click your project and go to properties then to the Signing Tab; uncheck the Sign the ClickOnce manifests and Sign the assembly.
I'm not sure what this does in terms of security but my app installed after I removed these options.