The Xamarin Android SDK Manager is not compatible with Visual Studio 2015.
(I’ll suggest you to use the latest version 15.6) Visual Studio 2017 version 15.5 or later is required. Visual Studio 2017 community edition or higher.So I really suggest you to download it.As stated in the official Xamarin website, the requirements are: I really don’t know why, but I know that the Xamarin Android SDK Manager is a very good tool. As you know is very important to keep your system updated and this of course is valid for the Android SDK.You should alway use the lasted available Android components.The Official Xamarin Documentation is not very clear on how to configure properly the Android SDK, so here is what you should do to obtain the best from your Xamarin.Android projects.First of all you should really install the Xamarin Android SDK Manager instead of the classic SDK Manager.Probably the most important reason to do so is that since version 25.2.3 of the Android SDK Tools package, Google replaced the UI Manager with a command line utility. Apache NetBeans can be installed on all operating systems that support Java, i.e, Windows, Linux, Mac OSX and BSD.