Dark data is the inactive or unused information organizations accumulate, often...

https://www.romeo-bookmarks.win/dark-data-is-the-inactive-or-unused-information-that-sits-in-your-storage-often

Dark data is the inactive or unused information organizations accumulate, often making up 55% of stored data. It raises breach and ransomware risks since unmonitored files may hold vulnerabilities. Storing this data also wastes money—sometimes $2