If you are looking at an older version (0.55), it likely predates Mac OS X or is from the early days of it. For modern usage and maximum stability, the current Reunion 14 is recommended.
Reunion is a premier genealogy application designed exclusively for macOS, known for helping users organize, research, and visualize their family history. The current version is 14, released as a 64-bit app that supports modern macOS systems and is able to open legacy data files from older versions, including those dating back to the 1990s. Reunion-0.55-mac.zip
Users can link multiple photos, videos, sound recordings, and documents (like wills or maps) to individual records. If you are looking at an older version (0
Reunion 14 is fully compatible with data from earlier versions (5-13), offering a direct upgrade path. The current version is 14, released as a
Features an interactive "tree view" that makes it easy to visualize and navigate through generations.
Reunion 14 for the Mac - Digital Download - S&N Genealogy Supplies
It allows for comprehensive data storage, including names, dates, places, notes, media (photos, documents), and research logs.