Dark data is the inactive or unused information your company keeps but doesn’t...

https://www.sierrabookmarking.win/dark-data-is-the-information-your-company-collects-but-doesn-t-use-often-55-or

Dark data is the inactive or unused information your company keeps but doesn’t analyze—around 60-80% of enterprise data. It can increase storage and backup costs and raise breach risks, including ransomware exposure