I know variations of this question have already been asked several times, but I\'ve tried several suggested solutions for other OPs, haven\'t been able to resolve this, and
This error mostly comes when angularjs is not able to locate the controller in any module. This can happen when you accidentally redefine the module. In your case i see that
window.app = angular.module('mean', ['ngCookies', 'ngResource', 'ui.bootstrap', 'ui.route', 'mean.system', 'mean.articles' ]);
and then
var mean = angular.module('mean',[]);
This syntax redefine the module.
To get the existing module using angular.module('mean')
without the second parameter.