How to get rid of old data

There's no really clean way to do this in Quicken Mac, as it does not have a year-end feature. It was designed to maintain a permanent history of financial transactions. I could describe how to select and delete selected transactions by date, but transfers between accounts and investment accounts that depend on acquisition dates of securities make it impractical and difficult to delete prior transactions. It can be done, but I don't advise it unless the sie of your file is causing major, major headaches.