conda 4.7.7 ->4.6 - Collecting package metadata (current_repodata.json) - (channel conda-forge) ipywidgets-5.2.3-py36_0 due to InvalidSpec: ==1.*

Question

conda update brakes everything.

conda env-solving took hours and forever

probably due to a conda optimization: https://www.anaconda.com/why-we-removed-the-free-channel-in-conda-4-7/

but that breaks many systems (like mine): https://github.com/conda/conda/issues/8844

got errors like

Collecting package metadata (current_repodata.json): - WARNING conda.models.version:get_matcher(531): Using .* with relational operator is superfluous and deprecated and will be removed in a future version of conda. Your spec was 1.*, but conda is ignoring the .* and treating it as 1
done
Solving environment: failed with current_repodata.json, will retry with next repodata source.
Initial quick solve with frozen env failed.  Unfreezing env and trying again.
Solving environment: failed with current_repodata.json, will retry with next repodata source.
Collecting package metadata (repodata.json): done

so I downgraded to conda=4.6

but got

Collecting package metadata: / WARNING conda.core.index:push_record(193): Skipping conda-forge/label/broken/linux-64::ipywidgets-5.2.3-py36_0 due to InvalidSpec: ==1.*
WARNING conda.core.index:push_record(193): Skipping conda-forge/label/broken/linux-64::ipywidgets-5.2.3-py27_0 due to InvalidSpec: ==1.*
WARNING conda.core.index:push_record(193): Skipping conda-forge/label/broken/linux-64::ipywidgets-5.2.3-py35_0 due to InvalidSpec: ==1.*
done
Solving environment: failed

InvalidVersionSpec: Invalid version '==1.*': invalid operator with '.*'

and

conda install conda=4.7 
Collecting package metadata: failed

CondaUpgradeError: This environment has previously been operated on by a conda version that's newer
than the conda currently being used. A newer version of conda is required.
  target environment location: /home/aeug/conda
  current conda version: 4.6.0
  minimum conda version: 4.7

Is there anything to fix the system / envs again?

All I can see is to reinstall with an good old conda 4.6.11 https://repo.anaconda.com/miniconda/

---

conda install conda=4.6
conda config --set pip_interop_enabled True

and I could rebuild the env with some errors but it took ~6 hours.

Answer 1

This solution helped my system, set a conda config parameter conda docs

conda config --set allow_conda_downgrades true
conda install conda=4.6.11

It works all right again.

Answer 2

I work with win10 1903, python 3.7 and conda 4.7.

I downgrade conda to 4.6.14 and reboot. Then everything works normally.