The issue
Today (31-Mar-2023) I downloaded Anaconda, uninstalled an older version and installed today's version on a Windows PC (private PC, no corporate firewall).
As suggested in another question Conda very slow and downloading only from conda forge? I removed the .condarc file, which must have been a leftover from a previous installation, as it contained conda-forge as the first repository.
I was testing if conda works properly, and a simple
conda update pandas
returned the oddest result ever: conda wanted to remove many packages, including numba and matplotlib. I report the exact text at the bottom.
Why should updating pandas result in the removal of all those packages?
What I have tried
I installed mamba, and a simple
mamba update pandas
tells me that All requested packages already installed - as one would expect having installed the whole of Anaconda just today
What I have researched
I hve found a similar issue reported here https://github.com/conda/conda/issues/8842 and Updating a specific module with Conda removes numerous packages However, if I understand correctly, in those cases the bug was caused by the fact that, over time, different versions of different packages had been installed, deviating from the anaconda installation. My case is different, because I downloaded Anaconda just today and I haven't changed nor updated any of those packages (the only change was installing mamba). I have been using Anaconda for 9 years and never encountered this.
The exact output from conda
The following packages will be REMOVED:
alabaster-0.7.12-pyhd3eb1b0_0
anyio-3.5.0-py310haa95532_0
appdirs-1.4.4-pyhd3eb1b0_0
argon2-cffi-21.3.0-pyhd3eb1b0_0
argon2-cffi-bindings-21.2.0-py310h2bbff1b_0
arrow-1.2.3-py310haa95532_1
astroid-2.14.2-py310haa95532_0
astropy-5.1-py310h9128911_0
asttokens-2.0.5-pyhd3eb1b0_0
atomicwrites-1.4.0-py_0
automat-20.2.0-py_0
autopep8-1.6.0-pyhd3eb1b0_1
babel-2.11.0-py310haa95532_0
backcall-0.2.0-pyhd3eb1b0_0
bcrypt-3.2.0-py310h2bbff1b_1
binaryornot-0.4.4-pyhd3eb1b0_1
black-22.6.0-py310haa95532_0
bleach-4.1.0-pyhd3eb1b0_0
blosc-1.21.3-h6c2663c_0
bokeh-2.4.3-py310haa95532_0
brotli-1.0.9-h2bbff1b_7
brotli-bin-1.0.9-h2bbff1b_7
cfitsio-3.470-h2bbff1b_7
charls-2.2.0-h6c2663c_0
cloudpickle-2.0.0-pyhd3eb1b0_0
colorcet-3.0.1-py310haa95532_0
comm-0.1.2-py310haa95532_0
constantly-15.1.0-py310haa95532_0
contourpy-1.0.5-py310h59b6b97_0
cookiecutter-1.7.3-pyhd3eb1b0_0
cssselect-1.1.0-pyhd3eb1b0_0
curl-7.87.0-h2bbff1b_0
cycler-0.11.0-pyhd3eb1b0_0
cytoolz-0.12.0-py310h2bbff1b_0
daal4py-2023.0.2-py310hf497b98_0
dal-2023.0.1-h59b6b97_26646
dask-2022.7.0-py310haa95532_0
dask-core-2022.7.0-py310haa95532_0
datashader-0.14.4-py310haa95532_0
datashape-0.5.4-py310haa95532_1
debugpy-1.5.1-py310hd77b12b_0
decorator-5.1.1-pyhd3eb1b0_0
diff-match-patch-20200713-pyhd3eb1b0_0
dill-0.3.6-py310haa95532_0
distributed-2022.7.0-py310haa95532_0
docstring-to-markdown-0.11-py310haa95532_0
docutils-0.18.1-py310haa95532_3
entrypoints-0.4-py310haa95532_0
et_xmlfile-1.1.0-py310haa95532_0
executing-0.8.3-pyhd3eb1b0_0
flake8-6.0.0-py310haa95532_0
flask-2.2.2-py310haa95532_0
flit-core-3.6.0-pyhd3eb1b0_0
fonttools-4.25.0-pyhd3eb1b0_0
fsspec-2022.11.0-py310haa95532_0
gensim-4.3.0-py310h4ed8f06_0
greenlet-2.0.1-py310hd77b12b_0
h5py-3.7.0-py310hfc34f40_0
hdf5-1.10.6-h1756f20_1
heapdict-1.0.1-pyhd3eb1b0_0
holoviews-1.15.4-py310haa95532_0
huggingface_hub-0.10.1-py310haa95532_0
hvplot-0.8.2-py310haa95532_0
hyperlink-21.0.0-pyhd3eb1b0_0
icc_rt-2022.1.0-h6049295_2
imagecodecs-2021.8.26-py310h4c966c4_2
imageio-2.26.0-py310haa95532_0
imagesize-1.4.1-py310haa95532_0
imbalanced-learn-0.10.1-py310haa95532_0
importlib-metadata-4.11.3-py310haa95532_0
importlib_metadata-4.11.3-hd3eb1b0_0
incremental-21.3.0-pyhd3eb1b0_0
inflection-0.5.1-py310haa95532_0
iniconfig-1.1.1-pyhd3eb1b0_0
intake-0.6.7-py310haa95532_0
intervaltree-3.1.0-pyhd3eb1b0_0
ipykernel-6.19.2-py310h9909e9c_0
ipython-8.10.0-py310haa95532_0
ipython_genutils-0.2.0-pyhd3eb1b0_1
ipywidgets-7.6.5-pyhd3eb1b0_1
isort-5.9.3-pyhd3eb1b0_0
itemadapter-0.3.0-pyhd3eb1b0_0
itemloaders-1.0.4-pyhd3eb1b0_1
itsdangerous-2.0.1-pyhd3eb1b0_0
jedi-0.18.1-py310haa95532_1
jellyfish-0.9.0-py310h2bbff1b_0
jinja2-time-0.2.0-pyhd3eb1b0_3
jmespath-0.10.0-pyhd3eb1b0_0
joblib-1.1.1-py310haa95532_0
jq-1.6-haa95532_1
json5-0.9.6-pyhd3eb1b0_0
jupyter-1.0.0-py310haa95532_8
jupyter_client-7.3.4-py310haa95532_0
jupyter_console-6.6.2-py310haa95532_0
jupyter_server-1.23.4-py310haa95532_0
jupyterlab-3.5.3-py310haa95532_0
jupyterlab_pygments-0.1.2-py_0
jupyterlab_server-2.19.0-py310haa95532_0
jupyterlab_widgets-1.0.0-pyhd3eb1b0_1
jxrlib-1.1-he774522_2
keyring-23.4.0-py310haa95532_0
kiwisolver-1.4.4-py310hd77b12b_0
lazy-object-proxy-1.6.0-py310h2bbff1b_0
lcms2-2.12-h83e58a3_0
libaec-1.0.4-h33f27b4_1
libbrotlicommon-1.0.9-h2bbff1b_7
libbrotlidec-1.0.9-h2bbff1b_7
libbrotlienc-1.0.9-h2bbff1b_7
libsodium-1.0.18-h62dcd97_0
libspatialindex-1.9.3-h6c2663c_0
libuv-1.44.2-h2bbff1b_0
libzopfli-1.0.3-ha925a31_0
llvmlite-0.39.1-py310h23ce68f_0
locket-1.0.0-py310haa95532_0
lxml-4.9.1-py310h1985fb9_0
lz4-3.1.3-py310h2bbff1b_0
lzo-2.10-he774522_2
m2w64-libwinpthread-git-5.0.0.4634.697f757-2
markdown-3.4.1-py310haa95532_0
matplotlib-3.7.0-py310haa95532_0
matplotlib-base-3.7.0-py310h4ed8f06_0
matplotlib-inline-0.1.6-py310haa95532_0
mccabe-0.7.0-pyhd3eb1b0_0
mistune-0.8.4-py310h2bbff1b_1000
mock-4.0.3-pyhd3eb1b0_0
mpmath-1.2.1-py310haa95532_0
msgpack-python-1.0.3-py310h59b6b97_0
multipledispatch-0.6.0-py310haa95532_0
munkres-1.1.4-py_0
mypy_extensions-0.4.3-py310haa95532_1
nbclassic-0.5.2-py310haa95532_0
nbclient-0.5.13-py310haa95532_0
nbconvert-6.5.4-py310haa95532_0
nest-asyncio-1.5.6-py310haa95532_0
networkx-2.8.4-py310haa95532_0
ninja-1.10.2-haa95532_5
ninja-base-1.10.2-h6d14046_5
nltk-3.7-pyhd3eb1b0_0
notebook-6.5.2-py310haa95532_0
notebook-shim-0.2.2-py310haa95532_0
numba-0.56.4-py310h4ed8f06_0
numpydoc-1.5.0-py310haa95532_0
openjpeg-2.4.0-h4fc8c34_0
openpyxl-3.0.10-py310h2bbff1b_0
pandocfilters-1.5.0-pyhd3eb1b0_0
panel-0.14.3-py310haa95532_0
param-1.12.3-py310haa95532_0
paramiko-2.8.1-pyhd3eb1b0_0
parsel-1.6.0-py310haa95532_0
parso-0.8.3-pyhd3eb1b0_0
partd-1.2.0-pyhd3eb1b0_1
pathspec-0.10.3-py310haa95532_0
patsy-0.5.3-py310haa95532_0
pep8-1.7.1-py310haa95532_1
pexpect-4.8.0-pyhd3eb1b0_3
pickleshare-0.7.5-pyhd3eb1b0_1003
plotly-5.9.0-py310haa95532_0
pooch-1.4.0-pyhd3eb1b0_0
poyo-0.5.0-pyhd3eb1b0_0
prometheus_client-0.14.1-py310haa95532_0
prompt-toolkit-3.0.36-py310haa95532_0
prompt_toolkit-3.0.36-hd3eb1b0_0
protego-0.1.16-py_0
ptyprocess-0.7.0-pyhd3eb1b0_2
pure_eval-0.2.2-pyhd3eb1b0_0
py-1.11.0-pyhd3eb1b0_0
pyasn1-0.4.8-pyhd3eb1b0_0
pyasn1-modules-0.2.8-py_0
pycodestyle-2.10.0-py310haa95532_0
pyct-0.5.0-py310haa95532_0
pycurl-7.45.1-py310hcd4344a_0
pydispatcher-2.0.5-py310haa95532_2
pydocstyle-6.3.0-py310haa95532_0
pyerfa-2.0.0-py310h2bbff1b_0
pyflakes-3.0.1-py310haa95532_0
pygments-2.11.2-pyhd3eb1b0_0
pyhamcrest-2.0.2-pyhd3eb1b0_2
pylint-2.16.2-py310haa95532_0
pylint-venv-2.3.0-py310haa95532_0
pyls-spyder-0.4.0-pyhd3eb1b0_0
pynacl-1.5.0-py310h8cc25b3_0
pyodbc-4.0.34-py310hd77b12b_0
pyparsing-3.0.9-py310haa95532_0
pyqtwebengine-5.15.7-py310hd77b12b_0
pytables-3.7.0-py310h388bc9b_1
pytest-7.1.2-py310haa95532_0
python-lsp-black-1.2.1-py310haa95532_0
python-lsp-jsonrpc-1.0.0-pyhd3eb1b0_0
python-lsp-server-1.7.1-py310haa95532_0
python-slugify-5.0.2-pyhd3eb1b0_0
python-snappy-0.6.1-py310hd77b12b_0
pytoolconfig-1.2.5-py310haa95532_1
pytorch-1.12.1-cpu_py310h5e1f01c_1
pyviz_comms-2.0.2-pyhd3eb1b0_0
pywavelets-1.4.1-py310h2bbff1b_0
pywin32-ctypes-0.2.0-py310haa95532_1000
pywinpty-2.0.10-py310h5da7b33_0
pyzmq-23.2.0-py310hd77b12b_0
qdarkstyle-3.0.2-pyhd3eb1b0_0
qstylizer-0.2.2-py310haa95532_0
qtawesome-1.2.2-py310haa95532_0
qtconsole-5.4.0-py310haa95532_0
queuelib-1.5.0-py310haa95532_0
regex-2022.7.9-py310h2bbff1b_0
requests-file-1.5.1-pyhd3eb1b0_0
rope-1.7.0-py310haa95532_0
rtree-1.0.1-py310h2eaa2aa_0
scikit-image-0.19.3-py310hd77b12b_1
scikit-learn-1.2.1-py310hd77b12b_0
scikit-learn-intelex-2023.0.2-py310haa95532_0
scipy-1.10.0-py310hb9afe5d_1
scrapy-2.8.0-py310haa95532_0
seaborn-0.12.2-py310haa95532_0
send2trash-1.8.0-pyhd3eb1b0_1
service_identity-18.1.0-pyhd3eb1b0_1
smart_open-5.2.1-py310haa95532_0
snappy-1.1.9-h6c2663c_0
sniffio-1.2.0-py310haa95532_1
snowballstemmer-2.2.0-pyhd3eb1b0_0
sortedcontainers-2.4.0-pyhd3eb1b0_0
sphinx-5.0.2-py310haa95532_0
sphinxcontrib-applehelp-1.0.2-pyhd3eb1b0_0
sphinxcontrib-devhelp-1.0.2-pyhd3eb1b0_0
sphinxcontrib-htmlhelp-2.0.0-pyhd3eb1b0_0
sphinxcontrib-jsmath-1.0.1-pyhd3eb1b0_0
sphinxcontrib-qthelp-1.0.3-pyhd3eb1b0_0
sphinxcontrib-serializinghtml-1.1.5-pyhd3eb1b0_0
spyder-5.4.1-py310haa95532_0
spyder-kernels-2.4.1-py310haa95532_0
sqlalchemy-1.4.39-py310h2bbff1b_0
stack_data-0.2.0-pyhd3eb1b0_0
statsmodels-0.13.5-py310h9128911_1
sympy-1.11.1-py310haa95532_0
tabulate-0.8.10-py310haa95532_0
tbb-2021.7.0-h59b6b97_0
tbb4py-2021.7.0-py310h59b6b97_0
tblib-1.7.0-pyhd3eb1b0_0
tenacity-8.0.1-py310haa95532_1
terminado-0.17.1-py310haa95532_0
text-unidecode-1.3-pyhd3eb1b0_0
textdistance-4.2.1-pyhd3eb1b0_0
threadpoolctl-2.2.0-pyh0d69192_0
three-merge-0.1.1-pyhd3eb1b0_0
tifffile-2021.7.2-pyhd3eb1b0_2
tinycss2-1.2.1-py310haa95532_0
tldextract-3.2.0-pyhd3eb1b0_0
tokenizers-0.11.4-py310he5181cf_1
tomli-2.0.1-py310haa95532_0
tomlkit-0.11.1-py310haa95532_0
transformers-4.24.0-py310haa95532_0
twisted-22.2.0-py310h2bbff1b_1
twisted-iocpsupport-1.0.2-py310h2bbff1b_0
typing-extensions-4.4.0-py310haa95532_0
typing_extensions-4.4.0-py310haa95532_0
unidecode-1.2.0-pyhd3eb1b0_0
w3lib-1.21.0-pyhd3eb1b0_0
watchdog-2.1.6-py310haa95532_0
wcwidth-0.2.5-pyhd3eb1b0_0
webencodings-0.5.1-py310haa95532_1
websocket-client-0.58.0-py310haa95532_4
werkzeug-2.2.2-py310haa95532_0
whatthepatch-1.0.2-py310haa95532_0
widgetsnbextension-3.5.2-py310haa95532_0
winpty-0.4.3-4
wrapt-1.14.1-py310h2bbff1b_0
xarray-2022.11.0-py310haa95532_0
xlwings-0.29.1-py310haa95532_0
yapf-0.31.0-pyhd3eb1b0_0
zeromq-4.3.4-hd77b12b_0
zfp-0.5.5-hd77b12b_6
zict-2.1.0-py310haa95532_0
zipp-3.11.0-py310haa95532_0
zope-1.0-py310haa95532_1
zope.interface-5.4.0-py310h2bbff1b_0
The following packages will be UPDATED:
ca-certificates conda-forge::ca-certificates-2022.12.~ --> pkgs/main::ca-certificates-2023.01.10-haa95532_0
conda conda-forge::conda-23.1.0-py310h5588d~ --> pkgs/main::conda-23.3.1-py310haa95532_0
conda-repo-cli 1.0.27-py310haa95532_0 --> 1.0.41-py310haa95532_0
jupyter_core 5.2.0-py310haa95532_0 --> 5.3.0-py310haa95532_0
libcurl 7.87.0-h86230a5_0 --> 7.88.1-h86230a5_0
packaging 22.0-py310haa95532_0 --> 23.0-py310haa95532_0
pcre2 conda-forge::pcre2-10.37-hdfff0fc_0 --> pkgs/main::pcre2-10.37-h0ff8eda_1
pkginfo 1.8.3-py310haa95532_0 --> 1.9.6-py310haa95532_0
reproc conda-forge::reproc-14.2.3-h8ffe710_0 --> pkgs/main::reproc-14.2.4-hd77b12b_1
reproc-cpp conda-forge::reproc-cpp-14.2.3-h0e605~ --> pkgs/main::reproc-cpp-14.2.4-hd77b12b_1
requests 2.28.1-py310haa95532_0 --> 2.28.1-py310haa95532_1
sqlite 3.40.1-h2bbff1b_0 --> 3.41.1-h2bbff1b_0
tornado 6.1-py310h2bbff1b_0 --> 6.2-py310h2bbff1b_0
tqdm 4.64.1-py310haa95532_0 --> 4.65.0-py310h9909e9c_0
urllib3 1.26.14-py310haa95532_0 --> 1.26.15-py310haa95532_0
zstd 1.5.2-h19a0ad4_0 --> 1.5.4-hd43e919_0
EDIT - UPDATE:
I gave up on Anaconda. I installed mambaforge on a PC without a proxy, and miniforge on a PC which accesses the internet via a proxy. mamba is faster than conda but doesn't work behind certain proxy/firewalls. I now have smaller environments with only the packages I need.
I still have no idea what caused the problem.