Environment inconsistent error when updating conda

Question

I am trying to install a package on Anaconda and I am keep getting environment inconsistent error. I have tried all the solutions in this post (I am listing them here) but the error remain the same:

1) update conda failed:

conda update --all

2) install anaconda failed:

 conda install anaconda

3) this one failed:

conda activate base
conda install anaconda
conda update --all

4) this one failed too:

conda install -c anaconda anaconda

I also tried updating the individual packages that cause inconsistency, for example I tried:

conda update seaborn 

In all the situations, I am getting the following error:

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

      - defaults/osx-64::scikit-learn==0.19.2=py37h4f467ca_0
      - defaults/osx-64::spyder==3.3.1=py37_1
      - defaults/osx-64::statsmodels==0.9.0=py37h1d22016_0
      - defaults/osx-64::anaconda-project==0.8.2=py37_0
      - defaults/osx-64::scipy==1.1.0=py37h28f7352_1
      - defaults/osx-64::patsy==0.5.0=py37_0
      - defaults/osx-64::anaconda-navigator==1.9.7=py37_0
      - defaults/osx-64::anaconda==5.3.1=py37_0
      - defaults/osx-64::pytables==3.4.4=py37h13cba08_0
      - defaults/osx-64::seaborn==0.9.0=py37_0
      - defaults/osx-64::scikit-image==0.14.0=py37h0a44026_1
      - defaults/osx-64::numexpr==2.6.8=py37h1dc9127_0
      - defaults/osx-64::anaconda-client==1.7.2=py37_0
      - defaults/osx-64::sphinx==1.7.9=py37_0
      - defaults/osx-64::mkl-service==1.1.2=py37h6b9c3cc_5
      - defaults/osx-64::conda==4.7.10=py37_0
      - defaults/osx-64::blaze==0.11.3=py37_0
      - defaults/osx-64::numpydoc==0.8.0=py37_0
      - defaults/osx-64::conda-build==3.15.1=py37_0

I then tried the following:

pip uninstall setuptools
conda install -c anaconda setuptools

When I finally tired updating the conda (conda update --all), I got the inconsistent error again as below:

The following packages are causing the inconsistency:

  - anaconda/osx-64::numba==0.46.0=py37h6440ff4_0
  - anaconda/osx-64::_anaconda_depends==2019.03=py37_0
  - anaconda/osx-64::blaze==0.11.3=py37_0
  - anaconda/osx-64::anaconda==custom=py37_1
failed
Solving environment: / 
Found conflicts! Looking for incompatible packages.
This can take several minutes.  Press CTRL-C to abort.
Examining setuptools:   4%|▋                | 14/379 [00:00<00:00, 12928.28it| ]
Comparing specs that have this dependency:   0%|         | 0/14 [00:00<?, ?it/s]
Finding shortest conflict path for setuptools:  50%|▌| 1/2 [00:05<00:05,  5.54s/Finding shortest conflict path for setuptools: 100%|█| 2/2 [00:05<00:00,  2.7- /C\ paring specs that have this dependency:   7%| | 1/14 [00:05<01:12,  5.60s/it]F/ ding shortest conflict path for setuptools:  20%|▏| 1/5 [00:00<00:00,  4.16itFinding shortest conflict path for setuptools:  40%|▍| 2/5 [00:00<00:00,  8.33it/s]

It has been 2 hours and the progress percentage has not been changed.

Here is information on my system:

macOS Mojave (version 10.14.6)

$ python
Python 3.7.5 (default, Oct 25 2019, 10:52:18) 
[Clang 4.0.1 (tags/RELEASE_401/final)] :: Anaconda, Inc. on darwin