Try this… Create a new ASP.NET Web Application (MVC or Web Forms).  Then add a new a WCF Workflow Service to your web project.

Now try to add a service reference to your workflow service.  It fails with an error.

There was an error downloading metadata from the address. Please verify that you have entered a valid address.

Why is this happening?

The most common reasons why this happens are

  1. The project won’t build for some reason
  2. Service Metadata is not enabled

How do I fix it?

  1. Build the solution and correct any compile errors.
  2. Start the solution and browse to the XAMLX file.

If you see this, your service does not have metadata enabled.

This is a Windows© Communication Foundation service.
Metadata publishing for this service is currently disabled.

How do I enable metadata?

The service page has some helpful tips to enable metadata for a WCF service.  Unfortunately the same tips do not apply to a WCF Workflow Service.  In previous releases of WCF you had to apply a service behavior using a named behavior configuration that applied to your service.  In .NET 4.0 or later you do not have to use a named behavior configuration and you don’t have to declare a <service> in your configuration file for more information on this see Simplified Configuration for WCF

Most of the time when creating Workflow Services you will use the default service configuration without declaring a <service> tag in your config file.  Enabling service metadata then is a simple matter of adding the following configuration.

<configuration>
  <system.serviceModel>
    <behaviors>
      <serviceBehaviors>
        <behavior name="">
          <serviceMetadata httpGetEnabled="True"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
  </system.serviceModel>
</configuration>

Happy Coding!

Ron Jacobs
twitter: @ronljacobs
blog: http://blogs.msdn.com/rjacobs