Well, here's the end of the LaCie saga: I was able with the app iSkysoft Data Recovery ro locate withn the Mac the corrupted LaCie disc with my backups from 2012 to 2014. I cannot save ths but it's on my desktop for now, and i am going download by download, extracting the Desktop for each download, taking the files I need and then backing them up to my latest 3TB LaCie. It's taking forever, but it's better than losing everything completely. I'm up to August 2013, and I had to skip three dates in 2012 fr now. Theu're karge, so I will download them last.
So, I'm proud of myself for accomplishing so much as a complete Computer Moron.