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Windows support

Windows versions as far back as Vista are fully supported when using the Ember CLI.

To get started ensure the following dependencies are installed:


Although supported, Windows performance, at least by default, isn't as good as on Linux or MacOS. On a positive note, this story continues to improve. Both Microsoft, and the Ember CLI team continue to work on improving these developer ergonomics.

What causes the build slowdown?

The two primary reasons are:

  • Lack of enabled-by-default symlinks
  • Generally slower filesystem operations on NTFS

Improving your Windows experience

Ensure Search and Defender ignore your project's tmp directory:

npm install -g ember-cli-windows

Then, to start the automatic configuration, run:


Make sure you use an elevated PowerShell. If there was an error, try executing Set-ExecutionPolicy Unrestricted -scope Process first.

Read more about this from the Microsoft DX Open Source team

To create symlinks the account running Ember CLI must have the SeCreateSymbolicLinkPrivilege. Users in the Administrators group have this permission already. However, if UAC (User Access Control) is enabled, users in the Administrators group must run their shell using Run As Administrator because UAC strips away certain permissions from the Administrators +group, including SeCreateSymbolicLinkPrivilege.

Run As Administrator

If the user account is not part of the Administrators group you will need to add the SeCreateSymbolicLinkPrivilege to allow the creation of symlinks. To do this open the Local Security Policy by typing Local Security Policy in the Windows Run Box.

Under Local Policies -> User Rights Assignment find the Create symbolic links policy and double-click it to add a new user or group. Once your user or group has been added, your user should be able to create symlinks. Keep in mind if your user is part of the Administrators group and UAC is enabled you will still need to start your shell using Run as Administrator.

Enabling Symlinks

Issues With npm: EEXISTS, Path too Long, etc

There were always two major issues with running Node.js on Windows: first and foremost, the operating system maintains a maximum length for path names, which clashes with Node's traditional way of nesting modules in node_modules. The second issue was a bit more subtle: The npm installer had a set of steps it executed for each package and it would immediately start executing them as soon as it decided to act on a package resulting in hard-to-debug race conditions.

npm 3 is a nearly complete rewrite of npm, fixing both issues. Windows users of Ember CLI might want to make the switch to npm 3 to benefit from its flat module installation (solving most issues involving long path names) as well as its multi-stage installer.