If you want to start fresh, you can delete the conda the directories .conda
and Miniconda
from your home directory.
Go to the Miniconda Website
Download and install the bash version of Miniconda for MacOSX to your Downloads
directory
In terminal, navigate to the Downloads directory and run
$ bash Miniconda3-latest-MacOSX-x86_64.sh
# or whatever the downloaded filename is
Install it
Install it Postgres.app
Install pgAdmin4
Install it in conda