Dark data is the inactive or unused information that sits in your systems—often...

https://alexisqoem867.trexgame.net/dark-data-vs-cold-data-are-they-the-same-thing

Dark data is the inactive or unused information that sits in your systems—often making up 60-80% of stored data. It increases storage and backup costs and raises ransomware and breach risks because it’s harder to monitor and protect