Dark data refers to the inactive or unstructured information stored but not...

https://wiki-dale.win/index.php/What_is_a_Smart_Data_Migration_and_When_Should_We_Do_It%3F

Dark data refers to the inactive or unstructured information stored but not used, often making up 55% of enterprise datasets. It increases storage and backup costs and exposes your systems to ransomware and breach risks