1. Confirm where your PostgreSQL is on your Mac, probably here:
/Library/PostgreSQL/x.y
"x.y" will be two numbers such as "8.4", "9.0", etc.
2. Open a terminal in "Utilities". In the terminal window copy/paste this:
sudo rm /Library/PostgreSQL/x.y/data/postmaster.pid
Substitute the "x.y" in that command with the numbers you noted in #1.
You want to delete "postmaster.pid" so answer "y" if the command finds it.
3. Next reboot and try starting PokerTracker 4 again.
If you have any further trouble please open a
Support Ticket along with your PokerTracker4.log file:
Guide: How to Create & Submit a PokerTracker4.log File