1. You have changed the name of the betting tab. All bets are stored by the name of the tab, so if you change the name of the tab, you will no longer be able to see previous bets placed by that tab. Think of it this way - if your betting tab is called "Lay Bets System 1", then when you click on View Betting Log, you will see any bets placed for the "Lay Bets System 1" system. If you then change the name of the tab to "Lay Fav" then you will only see any bets placed by the "Lay Favs" system. You will no longer be able to see bets placed by the "Lay Bets System 1" tab (unless you change the name of the betting tab back to "Lay Bets System 1".

or

2. Your Windows PC is not set up with a Date/Time format of dd/MM/yyyy which may prevent the database from correctly storing the betting history.