Dark data is the information companies collect but never use—up to 55% of...

https://www.first-bookmarkings.win/dark-data-is-the-dormant-info-businesses-keep-but-don-t-use-often-55-of-all

Dark data is the information companies collect but never use—up to 55% of stored data can be dark. It increases storage and backup costs and raises ransomware and breach risks because unused data often lacks proper security controls