I was facing this problem recently in a project when adding a reference to a WCF Service simply gave me this error.

I google’d it for a while but in vain, I also removed the auto-gen service entries from the web.config but that did not work either.

Then I realized that earlier I had deleted the Service References folder from the application root, re-add and it worked as expected.

Funny thing is that Visual Studio will not tell you what went wrong, neither folder name appears under Add > ASP.NET Folders nor Visual Studio attempts to recreate it.

Tags: Service References, Visual Studio, WCF