Solving environment: | Found conflicts! Looking for incompatible packages. The updating is eternal

Question

I have Ubuntu 18.04. I installed conda with python 2.7 some years ago. Finally I decided to pass to python 3.8 I create a new conda environment with python 3.8 and everything looked ok. When I tried to run a code by terminal, it printed:

ModuleNotFoundError: No module named 'numpy'

So I tip the command:

conda install numpy

and the terminal started an endless work. It printed:

Collecting package metadata (current_repodata.json): done Solving environment: \ The environment is inconsistent, please check the package plan carefully The following packages are causing the inconsistency:

[...a series of link...]

failed with initial frozen solve. Retrying with flexible solve. Solving environment: | Found conflicts! Looking for incompatible packages. This can take several minutes. Press CTRL-C to abort.

Later I report all the terminal output. Now it is examining conflicts with every packages of conda and it is working by hours. Somebody knows what has happened? Why it is not simply installing the packages?

Solution

I have solved it. I found another question with a similar situation: Anaconda environments packages update So I retry to install it using the pip line and it worked:

pip install numpy

I don't know why it doesn't work with the other way.