Error with Xamarin
this is what I do
1-install vs2015 pro licensed with xamarin
2-I believe project cross-plataform-blank app (xamarin form portable)
3-throws error "I FOUND A PROBLEM WHEN CREATING THE SUBPROJECT 'APP8.ANDROID'" REFERENCE TO OBJECT NOT ESTABLISHED AS AN INSTANCE OF AN OBJECT "
4-send error image
I found similar mistakes when I started using Xamarin, although not in particular. What I can suggest is the installation of several packages contained in Visual Studio, many of the problems I had were due to the lack of libraries, packages, repositories, etc. Maybe this will solve your problem.
To do this, in Windows, you must go to:
Control panel - > Uninstall Programs - > "your visual studio 2015" - > Change .
In the wizard that appears click on Modify .
Select Cross-platform mobile development - > Software development kit and common tools and brands all available packages that refer to Android.
Click on Next and wait for them to install.
I hope I have been of help,
Greetings!