Conda error on update: `conda.core.link:_execute(637): An error occurred while installing package 'None'. AssertionError()`

Question

Today when updating conda via conda update --all it downloads several packages and nearly completes installation but at the end, gives

Preparing transaction: done
Verifying transaction: done
Executing transaction: done
ERROR conda.core.link:_execute(637): An error occurred while installing package 'None'.
AssertionError()
Attempting to roll back.

Rolling back transaction: done

AssertionError()
()

Answer 1

The command conda install conda worked for me also when conda install anaconda failed for me. I am not sure why the latter does not work though. Otherwise I would get the ERROR conda.core.link:_execute(637) error.

Answer 2

The problem seems to be linked with old packages in the env that are not compatible with the version of the package you are trying to update. Resolved with the following steps:

1. updated packages in the env with dependencies for spyder 3.3.6

2. installed lattest vesrion of conda with

   conda install conda

3. updated spyder with:

   conda update spyder

After that everything was fine for me!