ClickOnce is displaying the '.application'

Question

I created a ClickOnce deployment of my test application, and I am trying to run it on my Windows XP SP2 test box. When I click on the install button that Visual Studio 2008 creates, all I get is the manifest file displayed in my browser and it doesn't spawn the install.

If I run the install against an Internet Explorer 7 test box, everything works OK.

How can I fix this problem?

Answer 1

One thing to check is if you have .NET 2.0 Framework installed on the XP box. Just an idea to try, this has come up for me in the past on Win2k machines.

The behavior you are describing can happen if .NET 2 is not installed, since the ".application" file extension would not be associated with anything.

Answer 2

There is also a browser setting that can cause this. Under Security is a setting, "Open files based on content, not file extension". In Internet Explorer 7 this does not affect ClickOnce applications, but in Internet Explorer 6 I have seen this setting cause the behavior you mentioned. Turning that setting off corrects the issue.

Answer 3

The first issue in the MSDN article Troubleshooting Specific Errors in ClickOnce Deployments addresses your issue.

Guy Starbuck is right, one issue could be the 2.0 Framework is not installed or corrupted. However, the issue I run into more often is not having the MIME type set up correctly in IIS for .application files. Make sure that IIS is set up to associate .application files with the application/x-ms-application content type.