Photos won't write to My Passport

I recently bought a 1 TB My Passport for Mac and went through the process of setting it up. I haven’t had a need to put anything on it until today, when I tried to export some photos onto it. First, I tried exporting from the Photos app and it said “operation failed - could not write to disk”. I then tried to export the photos from Lightroom and got the same result, and I finally tried dragging and dropping the photos from Finder, which gave me error code 50. And when I tried to format the drive, it once again gave me an error message, saying “unmounting disk…could not unmount disk”. What does this mean and how can I get around it? I set up the drive in a class and followed my professor’s exact instructions (she’s been in the photo/video industry for 20+ years, I thought she knew what she was talking about, but now I can’t use the drive other than to create folders, which I can’t even put anything in.


See if the following link helps: