Dark data is the 55% of your stored information that’s never accessed or used....

https://www.kilobookmarks.win/dark-data-is-the-unstructured-information-companies-collect-but-never-use

Dark data is the 55% of your stored information that’s never accessed or used. It’s more than wasted storage and backup costs—it also increases your risk of ransomware attacks and data breaches. This inactive data adds up to millions in annual expenses