In my Visual Studio solution I have both client projects and server side projects. The client projects are for Windows Phone, Xamarin iOS, Xamarin Android and WPF. The server side project is a Mobile Services .NET backend project.
My problems started yesterday when I would publish the latest update of my backend to Azure. I right clicked on the project and hit publish, then shown a dialog with the following text "object reference not set to an instance of an object". To verify if it was a problem with my project or with Visual Studio I created a new solution with a new Mobile Services .NET project, and it worked. Then added the project from the old solution to the new solution and it worked. Then I started to think about the diffrences in my both solutions, so I added new client projects. After that I have added a new iOS project I got the same error when I trying to publish the Mobile Services project to Azure. When I removed the iOS projects from the old soultion and restarted Visual Studio it worked there to.
I also tried to create a new solution with a MVC project and a Xamarin iOS project to investigate if the problem was just for Mobile Services projects or for all web projects. It looks like the problem is for all web projects when you have a Xamarin iOS project in the same solution.
I using Visual Studio 2013 with update 2.