There are two ways to install pgadmin. Using the PostgreSQL bundle that will install the postgresql server, pgadmin and everything else Installing only PgAdmin. Download the latest pgadmin from here https://www.postgresql.org/ftp/pgadmin/pgadmin4/v8.2/macos/ and install it. Do not delete the previously installed pgadmin or anything yet and try the newly installed pgadmin, if it works, simply delete the old one and replace it with the new one in the applications folder. Happy coding.