Dark data is the information your company collects but doesn’t use, often...

https://www.apu-bookmarks.win/dark-data-is-the-inactive-or-unused-information-organizations-keep-but-don-t

Dark data is the information your company collects but doesn’t use, often making up 55% of stored data. It takes up costly storage and backup space and increases risks like ransomware attacks or data breaches