ClickOnce Deployment Errors

Question

I am trying to deploy a ClickOnce app. It had worked previously when the server was just sitting with .Net 2.0 installed (no SP). Recently the server had 3.5SP1 installed on

Answer 1

Have you changed the target platform for the application itself? More importantly, does your development machine have .NET 3.5 SP-1 installed on it?

This error occurs when you have mismatched references. So your deployment expects one version, but the machine it's being installed on has a different version. It also happens if you have circular references.