You can't delete a single hand but you can purge a tournament from your database:
Guide: Purging Sessions & TournamentsBefore purging you should export the tournament from PokerTracker 4:
Guide: Exporting HandsYou can then manually import the exported tournament back into PokerTracker 4 via 'Play Poker -> Get Hands From Disk' after purging but if there is a specific hand causing an issue then you should delete it from the exported file using a text editor beforehand. If you want us to take a look at the issue then please attach the
original hand history file provided by your poker site (not the file exported by PokerTracker 4) and attach that to a
Support Ticket.