Dark data is the unused information that piles up in your storage, often making...

https://www.bookmark-fuel.win/dark-data-is-the-information-your-business-collects-but-never-uses-often-55-of

Dark data is the unused information that piles up in your storage, often making up 55% of all data. This inactive data wastes storage and backup costs and increases risk, like ransomware exposure due to overlooked files