My Passport Will Not Open Photos Library- Unsupported

I reformatted the external hard drive through Disk Utility and did a backup (many, many times) but when I try to open up my Photos Library, this message shows up: “These items cannot be added to your Photo library because the file format is not supported by Photos.” After scanning the internet and trying to find answers, I’m stumped. Does anybody have solutions to this issue?

macOS Sierra Version 10.12.6
MacBook Air (13-inch, Late 2010)