We wanted to let you know that we’ll be changing the signature verification process for ClickOnce applications and WPF XAML Browser Applications (XBAPs) in an upcoming update.  This change will help users recognize when they’re running untrusted applications from the Internet Zone, but may require you to make changes to your applications. Currently, applications configured to run “online-only” will not display notifications requesting that the user make a decision whether to run the application or not. After the update, users will see an Application Run dialog commonly encountered when accessing applications over the Internet using Internet Explorer.

In some situations you may want to retain the current application launch behavior. There are two ways to achieve this:

1.     Add the application publisher to the Trusted Publisher list. (http://msdn.microsoft.com/en-us/library/ms172241.aspx)

2.     Add the application URL to the Trusted Sites list (http://windows.microsoft.com/en-US/windows-vista/Security-zones-adding-or-removing-websites)