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Common issues

Having trouble with something? Check out these common pitfalls.

Don't install npm packages with sudo

Installing packages such as bower with sudo powers can lead to permissions issues and ultimately to problems installing dependencies. See https://gist.github.com/isaacs/579814 for a collection of various solutions.

Installing from behind a proxy

If you're behind a proxy, you might not be able to install because Ember CLI–or some of its dependencies–tries to git clone a git:// URL. (In this scenario, only http:// URLs will work).

You'll probably get an error like this:

npm ERR! git clone git://github.com/jgable/esprima.git Cloning into bare repository '/home/<username>/.npm/_git-remotes/git-github-com-jgable-esprima-git-d221af32'...
npm ERR! git clone git://github.com/jgable/esprima.git
npm ERR! git clone git://github.com/jgable/esprima.git fatal: unable to connect to github.com:
npm ERR! git clone git://github.com/jgable/esprima.git github.com[0:]: errno=Connection timed out
npm ERR! Error: Command failed: fatal: unable to connect to github.com:
npm ERR! github.com[0:]: errno=Connection timed out

As a workaround you can configure git to make the translation:

git config --global url."https://".insteadOf git://

Using Canary build instead of release

In most cases you should use a stable release, but if you need to install a canary version to test beta features, you'd do it like this:

For Ember: bower install ember#canary --resolution canary For ember-data: npm install --save-dev emberjs/data#master

Windows build performance issues

See The Windows Section for more details.

Cygwin on Windows

Node.js on Cygwin is no longer supported more details Rather then using Cygwin, we recommend running Ember CLI natively on windows, or via the new Windows Subsystem Linux.

Usage with Vagrant

Vagrant is a system for automatically creating and setting up development environments that run in a virtual machine (VM).

Running your Ember CLI development environment from inside of a Vagrant VM will require some additional configuration and will carry a few caveats.


In order to access your Ember CLI application from your desktop's web browser, you'll have to open some forwarded ports into your VM. Ember CLI by default uses two ports.

  • For serving assets the default is 4200. Can be configured via --port 4200.
  • For live reload there is no default. Can be configured via ---live-reload-port=9999.

To make Vagrant development seamless these ports will need to be forwarded.

Vagrant.configure("2") do |config|
  # ...
  config.vm.network "forwarded_port", guest: 4200, host: 4200
  config.vm.network "forwarded_port", guest: 9999, host: 9999

Watched Files

The way Vagrant syncs directories between your desktop and VM may prevent file watching from working correctly. This will prevent rebuilds and live reloads from working correctly. There are several workarounds:

  1. Watch for changes by polling the file system via: ember serve --watcher polling.
  2. Use nfs for synced folders.

VM setup

When setting up your VM, install Ember CLI dependencies as you normally would. Some of these dependencies (such as broccoli-sass) may have native dependencies that may require recompilation. To do so run:

npm rebuild


The two most common Vagrant providers, VirtualBox and VMware Fusion, will both work. However, VMware Fusion is substantially faster and will use less battery life if you're on a laptop. As of now, VirtualBox will use 100% of a single CPU core to poll for file system changes inside of the VM.