FATAL ERROR lock file “postmaster.pid” already exists

Question

I have recently installed PostGIS on my Mac (El Capitan 10.11.4, Postgres is version 9.5.1) using Homebrew, and I am following these instructions - http://morphocode.com/how-to-

Answer 1

My OSX laptop had shutdown unexpectedly, and I was getting a stale postmaster.pid error in the PostgresApp. Shutting down my laptop and turning it back on again solved the problem.