Transitioning from Anaconda's defaults channels

Users wishing to transition from Anaconda's defaults (i.e. those hosted under https://repo.anaconda.com/pkgs) channels should do so with care so as not to break their working environments. The first thing to realize is that in 2024 conda-forge is incompatible with the packages provided in defaults. Often, the packages on conda-forge will require newer versions of a particular package, or, may simply be organized in a different fashion. The only workflow we can support as a community is one where the conda-forge channel takes priority over all other channels.

If you were using Miniconda or Anaconda Distribution and wish to move to use conda-forge, we outline two workflows. The first allows you to try packages from conda-forge without uninstalling your previous installation, the second involves uninstalling Miniconda or Anaconda Distribution, and then installing Miniforge.

Trying conda-forge in an isolated environment

1. Create a conda environment with very few dependencies. The following command will only use packages from conda-forge to install Python 3.11. You may adjust the version of Python to the one of your liking:

   conda create --name conda-forge-env python=3 --channel conda-forge --override-channels

2. Activate your environment and add conda-forge with strict priority to that particular environment:

   conda activate conda-forge-env
   conda config --env --add channels conda-forge
   # optional:
   # conda config --env --remove channels defaults
   conda config --env --set channel_priority strict

3. Check the configuration of your conda environment:

   conda config --show

   This should report that conda-forge is the top most channel in your list.

4. You are now in a position to use command like:

   conda install my_desired_package_from_conda_forge

Uninstalling Anaconda and installing Miniforge

If you are ready to fully switch to conda-forge, we recommend uninstalling Anaconda / Miniconda and then installing Miniforge. The following steps are guidelines on how to go about this, while backing up your work and your environments.

1. Clean your existing conda installation. This should remove unused files from your Anaconda / Miniconda installation and make for smaller sized backup.

   # The conda build purge command may fail if you don't have conda-build installed.
   # this is expected
   conda build purge
   conda clean --all

2. Create a zip archive of your conda installation. Use your favorite graphical tool to right click on the Anaconda / Miniconda installation folder. Check if you have created additional environments outside the installation root by running conda info --envs. Back those up too, if necessary.

   • Alternatively, you can also export lockfiles for all your environments, if preferred:

     conda list --explicit --md5 --prefix /path/to/environment-name > environment-name.txt

     Note these lockfiles will only include the conda packages. If you pip installed packages on top, those won't be captured. Check conda-lock for those use cases.

   • Another useful file to create is the input environment.yml for each environment:

     conda env export --from-history --prefix --prefix /path/to/environment-name > environment-name.yml

     This file won't capture the exact same state you had in your environment. Instead it will tell conda what packages to look for and then find a solution that satisfies the request.

3. On Windows, use the uninstaller suggested by the system control panel. On Linux and macOS, you can delete the folder called anaconda3, or miniconda3 (usually located in your home directory).

4. Find the file called .condarc in your home directory, and back it up somewhere safe. Then, delete your old .condarc file. A new one specific to conda-forge will be created when we install Miniforge.

5. On Linux and macOS, your shell profile (~/.bashrc) might contain initialization code from the previous installation. Locate the block guarded by # >>> conda initialize >>> comments and delete it.

6. Download and install the Miniforge installer that matches your platform from the Miniforge download page.

7. Once installed, you should be able to use the Miniforge3 Prompt on Windows, or the terminal on Linux and macOS, to run the command:

   conda info

Notice that the conda-forge is the channel with the topmost priority.

You should now be in a position to use conda-forge packages.

A historical note

Until roughly 2021, conda-forge held strong compatibility with Anaconda's default channel. However, as announced in September 2021, we decided toultimately move away from dependency on Anaconda's defaults packages. Over the years, this has led for more divergence between package versions, and names between conda-forge and Anaconda's defaults channel.

In 2024, the workflow that has packages co-installed from Anaconda's channel and conda-forge is no longer supported.

To check if you have packages installed from both sources, use the command

conda list --show-channel-urls

All packages should specify that they have been installed from the conda-forge channel. In 2024, there still exist a few bugs where conda packages will claim that they have been installed from PyPI even though they have been installed from conda-forge.