I have a couple of Xamarin forms projects where the PCL has stopped building with the error:
There was a mismatch between the processor architecture of the project being built "MSIL" and the processor architecture of the reference "C:\Windows\Microsoft.NET\Framework\v4.0.30319\mscorlib.dll", "x86". This mismatch may cause runtime failures. Please consider changing the targeted processor architecture of your project through the Configuration Manager so as to align the processor architectures between your project and references, or take a dependency on references with a processor architecture that matches the targeted processor architecture of your project.
I have checked out previous versions of the projects and they are failing similarly.
The only difference I am aware of is that one night Windows Update forced a restart and installed an update.
I am using Visual Studio 2015 and both projects are targetting .Net 4.5 one with profile 111 and the other with profile7.
The projects also fail to build with the same error using Xamarin studio.
How do I resolve the issue?