C++ – VS 2015 Cannot open compiler generated file: ”: Invalid argument

The standard header is called <fstream>.

Edit: Since the headers were renamed without the .h extension, all symbols were moved to the std:: namespace. You might want to add a using namespace std; directive or qualify cin, cout and fstream in your code.

The properties explorer is where you want to look. Afxwin.h is in ..\atlmfc\include, tchar.h and cassert are in ..\include which you'd think would be a global-type property, but it turns out it's not so simple. This is the biggest problem I had with upgrading from 2008. This is no longer an application option, it's a user property.

Before you go about changing things, look the properties explorer and read the MSBuild documentation, because, while the new format is more powerful and flexible, but it doesn't upgrade from the old format gracefully.