How to reproduce: Try installing gulp.
What expected: green hexagon of gulp under npm dependencies in solution explorer with disclosure symbol for showing sub-dependencies.
Actual result: npm tree is ABSOLUTELY empty, previously installed packages are not shown, npm manager fails to open, saying package.json is broken.
https://github.com/joyent/node/issues/6960#issuecomment-45569604
That could be an isuue of npm itself, but from topic on github it seems like only Windows Explorer and Cmd from the relevant contractants have the problem with long path folder view.
Propotision: please check whether NodejsTool for Visual Studio use UNC path system everywhere and not relative paths to manage packages.