The easiest way to install ess is using conda. Packages from Anaconda Cloud are available for Linux, macOS, and Windows. It is recommended to create an environment rather than installing individual packages.

Install mamba#

Instead of conda, we recommend mamba as a conda package manager. It is known that conda can be very slow and mamba can solve the problem. You can install mamba with the command below.

conda install mamba -n base -c conda-forge

Once mamba is installed, you can replace conda with mamba when you install any packages or create an environment.

Use the provided environment file#

  1. Download ess.yml.

  2. In a terminal run:

    conda activate
    mamba env create -f ess.yml  # same as ``conda env create -f ess.yml``
    conda activate ess
    jupyter lab

The conda activate ensures that you are in your base environment. This will take a few minutes. Above, replace ess.yml with the path to the download location you used to download the environment. Open the link printed by Jupyter in a browser if it does not open automatically.

If you have previously installed ess with conda we nevertheless recommend creating a fresh environment rather than trying to conda update. You may want to remove your old environment first, e.g.,

conda activate
conda env remove -n ess

and then proceed as per instructions above. The conda activate ensures that you are in your base environment.

Using Mantid#

If you want to install mantid alongside ess in your environment, use the ess-mantid.yml environment file instead:

mamba env create -f ess-mantid.yml  # same as ``conda env create -f ess-mantid.yml``

conda activate ess-mantid
jupyter lab

Without the provided environment file#

To create a new conda environment with ess:

mamba create -n env_with_ess -c conda-forge -c scipp ess

To add ess to an existing conda environment:

mamba install -c conda-forge -c scipp ess


Installing ess on Windows requires Microsoft Visual Studio 2019 C++ Runtime installed. Visit this page for the up to date version of the library.

After installation the modules ess, scippneutron, and scipp can be imported in Python. Note that only the bare essential dependencies are installed.

To update or remove ess use conda update and conda remove.