To give you the best advice on that specific file ( Reunion-0.55-mac.zip ), could you let me know: What are you running? Are you trying to open old data from a vintage Mac?
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. To give you the best advice on that