Hello all! 
First, sorry to my bad english, i am studying to improve this.
Ok, i am newbie here in the forum and i have a problem ! 
I searched in others platforms (github, stack) and i can not find solution to my problem.
I have installed 4 frameworks, when start the simple project: "File > New Project > ASP.Net core Web Application"  everything works fine, but when I try to use a blank solution to
 separate the projects into layers, visual studio shows this error. 
links image problem:
http://imgur.com/X7CiwsH
http://imgur.com/QUJfU9y
> I've already tried putting a global.json at the rootof every project.
> I've already tried uninstalling and installing all frameworks.
> I've already tried uninstalling and installing my visual studio