Installing express in Terminal on Mac - node.js

Question

I get this code. I am on a Mac. I have installed npm. I am an Admin. What am I doing wrong? I've been googling for hours.
Matts-MacBook-Pro-3:Start Matt$ npm install express-generator -g
npm WARN checkPermissions Missing write access to /usr/local/lib/node_modules/express-generator
npm WARN checkPermissions Missing write access to /usr/local/lib/node_modules
/usr/local/lib
└── express-generator#4.13.1
npm ERR! Darwin 14.5.0
npm ERR! argv "/usr/local/bin/node" "/usr/local/bin/npm" "install" "express-generator" "-g"
npm ERR! node v5.3.0
npm ERR! npm v3.3.12
npm ERR! path /usr/local/lib/node_modules/express-generator
npm ERR! code EACCES
npm ERR! errno -13
npm ERR! syscall access
npm ERR! Error: EACCES: permission denied, access '/usr/local/lib/node_modules/express-generator'
npm ERR! at Error (native)
npm ERR! { [Error: EACCES: permission denied, access '/usr/local/lib/node_modules/express-generator']
npm ERR! errno: -13,
npm ERR! code: 'EACCES',
npm ERR! syscall: 'access',
npm ERR! path: '/usr/local/lib/node_modules/express-generator' }
npm ERR!
npm ERR! Please try running this command again as root/Administrator.
npm ERR! Please include the following file with any support request:
npm ERR! /Users/Matt/Start/Start/npm-debug.log
Matts-MacBook-Pro-3:Start Matt$

Answer 1

Try clearing the npm cache and try the npm install again. You can use the following to clear the npm cache.
npm cache clean <path to express-generator>
Sometimes you get this error even when you are on ssh, the npm registry might be configured to use a different registry for npm packages and that registry might not have a express-generator