Did you really install VS2015?
Do you have "Microsoft Visual Studio 2015" in Control Panel\All Control Panel Items\Programs and Features?
If so then select it and press "Change" and make sure to install C++.
The good thing is that typically users do not notice. The problem is popping up when trying to compile with older compilers or you remember that such stuff was not possible in the past.
As @mcosta suggests there is probably a recommendation out. On the other compiler versions are changing too rapidly and also the versions of recommendations.