Dark data is the information your company collects but doesn’t use or manage....

https://www.normalbookmarks.win/dark-data-is-the-inactive-or-unused-information-stored-across-your

Dark data is the information your company collects but doesn’t use or manage. It often makes up 55% of data stored, leading to wasted storage and backup costs. Plus, it increases ransomware and breach risks since unmanaged data is harder to protect