Dark data refers to information your company collects but never uses—often...

https://www.bookmarkidea.win/dark-data-is-the-unused-untagged-information-that-piles-up-inside-your-storage

Dark data refers to information your company collects but never uses—often making up 55% of stored files. This unused data takes up space, drives up storage and backup costs, and increases ransomware risk since it’s often unmonitored