CS0234: The type or namespace name ‘System’ does not exist in the namespace ‘Windows.’ when running Cordova for WP8

All this cryptic error messages really says is…use the 64 bit version of Windows, not the 32 bit as the cordova docs suggest.

As a tip to prevent much pain, suffering and tears, the Windows Phone emulator will NOT run in in a nested virtualisation environment, at least not when I tried it on Virtualbox. e.g. it won’t run on a mac running Virtualbox containing Windows.

Bootcamp or something similar is probably your best bet for running it on a mac. Or a windows phone device, though Parallels users might have better luck.