XDescProc.exe is holding on to a named mutex

We are using Visual Studio 2012 with the Caliburn.Micro framework. As part of that framwork there is an AppBootstrapper which is called as soon as the application starts. Within this application we have a named mutex which is used to prevent the application from being executed more than once. The problem is that whenever XDescProc runs is causes the mutex to be created. I can only guess that somehow it is instantiating our AppBootstrapper so the mutex gets created and the next time we try to debug the app we get told it is already running. I have proved this by killing the XDescProc processes which clears the problem. As soon as you view another XAML file it happens again.

Is there any way around this? Are we doing something wrong?

Regards

Celestrium