ClickOnce is a great technology that blurs the line between web and client(windows) applications. You can use it to easily deploy windows forms and WPF (through XBAP) app's. However there is common problem with it. The application store (the place where all ClickOnce applications get stored) has the ability to corrupt it self ending in an appropriate version mix of your application. You can end up in situation where "it works on my machine", but in reality the application did not work correctly. To avoid such situation it is a good practice to clear your application store before testing the deployment locally on your machine. You can do that using a magic (I mean it for real) command. Open Visual Studio command prompt and type:
mage -cc
And a magic happens ;)