Unable to attach debugger to a process running as different user Visual Studio 2012/2013

I have a Windows Service running as a low privileged domain account. My account is a local administrator. When I try to attach the debugger to the service when the project/solution is open in Visual Studio 2012/2013 I get the error "Unable to attach to process. Operation not supported. Unknown error: 0x80072ee6." Did not have the problem up to VS 2010.

If I close the project/solution and try again, I am able to attach. This is reproducible every time.

My setup: Windows Server 2008 R2 64 bit. Visual Studio 2013 Ultimate (had same issue in 2012) running as my domain account which is part of local administrator group. MSIL Windows Service running as 64 bit. Running locally. Built with C#/.NET 4.5.1

How can I keep the project/solution open and attach the debugger to this process?