How You Can Lose File Despite 3 Layers of Backup?

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How You Can Lose a File Despite Three Layers of Backup (and How To Avoid It)
I have preached the gospel of file backups for decades, from floppies through digital tape systems to today’s local and cloud-based systems for continuous archiving of even the tiniest changes to files. Color me a rainbow for how surprised I was a few days ago when I found I had permanently lost the original form of a file that a colleague had shared with me 45 days earlier. And it was my own fault.