If I follow this steps to create a new app:
Rubens-MacBook-Pro:~ rlopez$ npm install -g cordova ionic
Rubens-MacBook-Pro:~ rlopez$ ionic start myApp tabs
Rubens-
My problem wasn't permissions... I couldn't quite find the origin of the problem but I did a workaround. this error was happening when I was trying to add a plugin which wasn't updated to the new files/folder system.
cordova platform android -v
it returned -> 8.0.0
What I did was:
cordova platform rm android
cordova platform add android@6.4.0
and then:
cordova plugin add
This way the plugin installation showed no errors.. but keep in mind that after the cordova plugin add command, the android platform version automatically updated to 8.0.0 again... so I had to repeat the process in order to add another plugin with the same issue.
After repeating this process 2 times I finally got the project to run with the 2 plugins installed