title: Solving environment: | Found conflicts! Looking for incompatible packages. The updating is eternal
body: <p>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:</p>
  <blockquote>
  <p>ModuleNotFoundError: No module named 'numpy'</p>
  </blockquote>
  <p>So I tip the command:</p>
  <blockquote>
  <p>conda install numpy</p>
  </blockquote>
  <p>and the terminal started an endless work. It printed:</p>
  <blockquote>
  <p>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:</p>
  </blockquote>
  <p>[...a series of link...]</p>
  <blockquote>
  <p>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.</p>
  </blockquote>
  <p>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?</p>