Please restart your computer and then uninsall PostgreSQL (the program where PokerTracker 4 stores your poker data) if it is listed. Next manually download and install PostgreSQL v12 from
here and for the two password boxes use 'dbpass' (no quotes) which is what PokerTracker 4 uses by default. At the end of the install it will tell you if it installed successfully or not. If that PostgreSQL installs successfully try starting PokerTracker 4 again.