How to install pgAdmin 4 in desktop mode on Ubuntu
askubuntu.com › questions › 831262Sep 29, 2016 · Conflict with pgAdmin 3 configuration. pgAdmin 4 will not start in the environment where pgAdmin 3 was previously installed and used because of incompatible configuration in the .pgadmin directory. The simplest solution is to either clear that directory or tweak config_local.py to point to a clean new .pgadmin4 directory.