Xamarin Forms Portable Application MonoAndroid Build Error - Framework not found

Question

I've made a fresh Xamarin Forms Portable Project from the Cross Platform templates in Visual Studio 2015. Haven't touched or modified any of the project files. Then When I try to initially build it, I get the following build error:

C:\Program Files (x86)\MSBuild\14.0\bin\Microsoft.Common.CurrentVersion.targets(1098,5): error MSB3644: The reference assemblies for framework "MonoAndroid,Version=v6.0" were not found. To resolve this, install the SDK or Targeting Pack for this framework version or retarget your application to a version of the framework for which you have the SDK or Targeting Pack installed. Note that assemblies will be resolved from the Global Assembly Cache (GAC) and will be used in place of reference assemblies. Therefore your assembly may not be correctly targeted for the framework you intend.

My Project defaults are:

Looking at similar questions, it would seem that, indeed, that version of the framework is not installed. But it seems to be. Android SDK Manager shows the following:

What is going on here? How can I resolve this.

Answer 1

When you get these type of errors, that are really 'out there' and hint of system configuration problems, it's time to reinstall.

I had to completely remove all remnants of Visual Studio, SDKs and Xamarin. 'Modify' and 'Repair' didn't work.

After the complete fresh install of VS 2015 and Xamarin, things are back to normal.