I have tried to add a Visual Studio 2015 export target to an already functioning OSX AudioPlugin jucer file.
It appears that only the old JSON-based modules are being detected (I’ve tried by referencing a JUCE 4.1 folder.)
If I choose a folder with the latest JUCE 4.2 version, the modules are not detected, and thus project can’t be exported and opened in the IDE.
I compiled the Projucer a few hours ago from the current git version.
Maybe the problem also occurs with other MSVS exporters, I did not try.
Hopefully it’s an easy fix for you!