When you get a new version of the Web Tools for Visual Studio, presumably this version of npm gets updated. This also means that unless you tell Visual Studio otherwise, the npm and node you get when running a build in VS is gonna be different than if you do it outside - if you stick with the default settings. It's easily updated. When you install Visual C++ for Cross-Platform Mobile Development, Visual Studio can communicate with vcremote, a remote agent running on your Mac to transfer files, build and run your iOS app, and send debugging commands.
If all the above options fail, try installing it from the command-line. Here's how (on StackOverflow): VSIXInstaller.exe /quiet someextension.vsix You can find VSIXInstaller here (on your local PC - depending on the Visual Studio version replace 14.0 by the version you're using): C: Program Files (x86) Microsoft Visual Studio 14.0 Common7 IDE To display the installer dialog(s), remove the /quiet option.
Note:. To uninstall a VSIX extension, you need to know its vsixID ( is described how to get it), then you can use VSIXInstaller.exe /uninstall:vsixID. To install/uninstall VSIX files for a specific Visual Studio version, use the switches /skuName:name and /skuVersion:version; you can see all options of the command line tool if you type VSIXInstaller.exe /? In the developer command prompt.