Conda env update hangs indefinitely on Mac M4 following installation instructions

[LekiaAnonim]

Issue:

While attempting to install RMG using the instructions provided in the Anaconda Developer Installation Guide, I encountered an issue where the conda env update -f environment.yml command hangs indefinitely during the "Solving environment" step.

• OS: macOS (Apple Silicon M4)

Observed Behavior:

The conda solver hangs indefinitely at the environment-solving stage and does not proceed.

Temporary Workaround:

I was able to bypass this issue with the following steps:

1. In the environment.yml file:

• Reordered the channels to place conda-forge above rmg.
• Removed cantera from the channel list.
• Commented out the cantera and julia packages.

2. Ran conda env update -f environment.yml — it completed successfully.

3. Re-added cantera to the channels and uncommented cantera and julia packages.

4. Re-ran conda env update -f environment.yml — it completed successfully on the second attempt.

Request:

It would be helpful if this issue could be investigated further. Perhaps certain package versions or channel priorities are causing conflicts or solver inefficiencies specific to newer Apple Silicon systems (e.g., M4).

Thank you!

[JacksonBurns]

Weird! Thanks for putting together a workaround. Can you show the output of conda info -a?

[LekiaAnonim]

Thanks @JacksonBurns . Here's the output of conda info -a

active environment : rmg_env
    active env location : /opt/anaconda3/envs/rmg_env
            shell level : 2
       user config file : /Users/lekiaprosper/.condarc
 populated config files : /opt/anaconda3/.condarc
                          /Users/lekiaprosper/.condarc
                          /opt/anaconda3/envs/rmg_env/.condarc
          conda version : 24.11.3
    conda-build version : 25.4.2
         python version : 3.12.7.final.0
                 solver : libmamba (default)
       virtual packages : __archspec=1=x86_64
                          __conda=24.11.3=0
                          __osx=15.5=0
                          __unix=0=0
       base environment : /opt/anaconda3  (writable)
      conda av data dir : /opt/anaconda3/etc/conda
  conda av metadata url : None
           channel URLs : https://repo.anaconda.com/pkgs/main/osx-64
                          https://repo.anaconda.com/pkgs/main/noarch
                          https://repo.anaconda.com/pkgs/r/osx-64
                          https://repo.anaconda.com/pkgs/r/noarch
          package cache : /opt/anaconda3/pkgs
                          /Users/lekiaprosper/.conda/pkgs
       envs directories : /opt/anaconda3/envs
                          /Users/lekiaprosper/.conda/envs
               platform : osx-64
             user-agent : conda/24.11.3 requests/2.32.3 CPython/3.12.7 Darwin/24.5.0 OSX/15.5 solver/libmamba conda-libmamba-solver/24.9.0 libmambapy/1.5.8 aau/0.4.4 c/_S3wHmOLJIb5u62Vqnvhqg s/BBpCuaVUWEkgQzlspThtMA e/NBySWfyCn5ey80a1m7nNkw
                UID:GID : 501:20
             netrc file : None
           offline mode : False


# conda environments:
#
base                   /opt/anaconda3
rmg_env              * /opt/anaconda3/envs/rmg_env
rmg_venv               /opt/anaconda3/envs/rmg_venv

sys.version: 3.12.7 | packaged by Anaconda, Inc. | (m...
sys.prefix: /opt/anaconda3
sys.executable: /opt/anaconda3/bin/python
conda location: /opt/anaconda3/lib/python3.12/site-packages/conda
conda-build: /opt/anaconda3/bin/conda-build
conda-content-trust: /opt/anaconda3/bin/conda-content-trust
conda-convert: /opt/anaconda3/bin/conda-convert
conda-debug: /opt/anaconda3/bin/conda-debug
conda-develop: /opt/anaconda3/bin/conda-develop
conda-env: /opt/anaconda3/bin/conda-env
conda-inspect: /opt/anaconda3/bin/conda-inspect
conda-metapackage: /opt/anaconda3/bin/conda-metapackage
conda-pack: /opt/anaconda3/bin/conda-pack
conda-render: /opt/anaconda3/bin/conda-render
conda-repo: /opt/anaconda3/bin/conda-repo
conda-server: /opt/anaconda3/bin/conda-server
conda-skeleton: /opt/anaconda3/bin/conda-skeleton
conda-token: /opt/anaconda3/bin/conda-token
user site dirs: ~/.local/lib/python3.12

CIO_TEST: <not set>
CMAKE_PREFIX_PATH: :/opt/anaconda3/envs/rmg_env
CONDA_ALLOW_SOFTLINKS: false
CONDA_BACKUP_HOST: Lekias-MacBook-Pro.local
CONDA_DEFAULT_ENV: rmg_env
CONDA_EXE: /opt/anaconda3/bin/conda
CONDA_JL_CONDA_EXE: /opt/anaconda3/bin/conda
CONDA_JL_CONDA_EXE_BACKUP: 
CONDA_JL_HOME: /opt/anaconda3/envs/rmg_env
CONDA_JL_HOME_BACKUP: 
CONDA_PREFIX: /opt/anaconda3/envs/rmg_env
CONDA_PREFIX_1: /opt/anaconda3
CONDA_PROMPT_MODIFIER: (rmg_env) 
CONDA_PYTHON_EXE: /opt/anaconda3/bin/python
CONDA_ROOT: /opt/anaconda3
CONDA_SHLVL: 2
CONDA_TOOLCHAIN_BUILD: x86_64-apple-darwin13.4.0
CONDA_TOOLCHAIN_HOST: x86_64-apple-darwin13.4.0
CURL_CA_BUNDLE: <not set>
C_INCLUDE_PATH: /opt/homebrew/Cellar/libxc/7.0.0/include
GPAW_SETUP_PATH: /Users/lekiaprosper/anaconda3/lib/python3.12/site-packages/gpaw_data/setups
JULIA_DEPOT_PATH: /opt/anaconda3/envs/rmg_env/share/julia:
JULIA_LOAD_PATH: @:@rmg_env:@stdlib
LD_LIBRARY_PATH: /opt/homebrew/Cellar/libxc/7.0.0/install/lib
LD_PRELOAD: <not set>
LIBRARY_PATH: /opt/homebrew/Cellar/libxc/7.0.0/lib
PATH: /opt/anaconda3/envs/rmg_env/bin:/opt/anaconda3/condabin:/Users/lekiaprosper/.juliaup/bin:/Users/lekiaprosper/.local/bin:/Users/lekiaprosper/.nvm/versions/node/v22.14.0/bin:/opt/homebrew/bin:/Users/lekiaprosper/Documents/CoMoChEng/RMG/RMG-Py:/Library/Frameworks/Python.framework/Versions/3.7/bin:/Library/Frameworks/Python.framework/Versions/3.10/bin:/Users/lekiaprosper/Documents/CoMoChEng/RMG/RMG-Py:/Library/Frameworks/Python.framework/Versions/3.9/bin:/Library/Frameworks/Python.framework/Versions/3.13/bin:/usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin:/Library/Apple/usr/bin:/Library/TeX/texbin
PYTHONPATH: /Users/lekiaprosper/Documents/CoMoChEng/RMG/RMG-Py/:/Users/lekiaprosper/Documents/CoMoChEng/RMG/RMG-Py/:
REQUESTS_CA_BUNDLE: <not set>
SSL_CERT_FILE: <not set>

[JacksonBurns]

Thanks @LekiaAnonim. Your conda is appropriately configured with libmamba as the solver, which is unfortunately our 'only dance move' when it comes to fixing environment hangs. For the time being, this workaround will just be the solution.

The good news is that in #2741 I have updated RMG in such a way that the ARM Mac-specific instructions are no longer needed, and one can run RMG-Py without x64 emulation. Once that version is merged and release as RMG 3.3 this will be resolved.