56 Anaconda 更新に引っかかる

% conda update conda; conda update --all
Error while loading conda entry point: conda-libmamba-solver (dlopen(/opt/anaconda3/lib/python3.12/site-packages/libmambapy/bindings.cpython-312-darwin.so, 0x0002): Library not loaded: @rpath/libarchive.20.dylib
  Referenced from: <496442DC-0EDE-3705-A2B5-401A4FC0D733> /opt/anaconda3/lib/libmamba.2.0.0.dylib
  Reason: tried: '/opt/anaconda3/lib/libarchive.20.dylib' (no such file), '/opt/anaconda3/lib/python3.12/site-packages/libmambapy/../../../libarchive.20.dylib' (no such file), '/opt/anaconda3/lib/python3.12/site-packages/libmambapy/../../../libarchive.20.dylib' (no such file), '/opt/anaconda3/bin/../lib/libarchive.20.dylib' (no such file), '/opt/anaconda3/bin/../lib/libarchive.20.dylib' (no such f
ile), '/usr/local/lib/libarchive.20.dylib' (no such file), '/usr/lib/libarchive.20.dylib' (no such file, not in dyld cache))
Retrieving notices: done

CondaValueError: You have chosen a non-default solver backend (libmamba) but it was not recognized. Choose one of: classic

Error while loading conda entry point: conda-libmamba-solver (dlopen(/opt/anaconda3/lib/python3.12/site-packages/libmambapy/bindings.cpython-312-darwin.so, 0x0002): Library not loaded: @rpath/libarchive.20.dylib
  Referenced from: <496442DC-0EDE-3705-A2B5-401A4FC0D733> /opt/anaconda3/lib/libmamba.2.0.0.dylib
  Reason: tried: '/opt/anaconda3/lib/libarchive.20.dylib' (no such file), '/opt/anaconda3/lib/python3.12/site-packages/libmambapy/../../../libarchive.20.dylib' (no such file), '/opt/anaconda3/lib/python3.12/site-packages/libmambapy/../../../libarchive.20.dylib' (no such file), '/opt/anaconda3/bin/../lib/libarchive.20.dylib' (no such file), '/opt/anaconda3/bin/../lib/libarchive.20.dylib' (no such file), '/usr/local/lib/libarchive.20.dylib' (no such file), '/usr/lib/libarchive.20.dylib' (no such file, not in dyld cache))

CondaValueError: You have chosen a non-default solver backend (libmamba) but it was not recognized. Choose one of: classic

 %

あれ？どうしたのかな。

1756>>https://stackoverflow.com/questions/77617946/solve-conda-libmamba-solv er-libarchive-so-19-error-after-updating-conda-to-231756>>

色々やってみたが、即ダメ、となるものが多かった。次が当たりだった。

conda install --solver=classic conda-forge::conda-libmamba-solver conda-forge::l
ibmamba conda-forge::libmambapy conda-forge::libarchive

conda update conda; conda update -all がとおるようになった。