Creating new VS2015 exporter, VS doesn't recognise JUCE symbols

I had a fresh GUI app with XCode exporter, working fine in OSX.

I open up the projucer file in Windows projucer, create new exporter (VS2015) -> “save and open in IDE”.

But every single JUCE thing, like Component flags an error.

Oddly the #include ../JuceLibraryCode/JuceHeader.h succeeds…

I look in that .h I see that all of the various juce #includes fail, e.g.

#include <juce_audio_basics/juce_audio_basics.h> // Error: cannot open source file

What’s going on?