Dark data is all the information companies collect but never use—often 60-80%...

https://tiny-wiki.win/index.php/How_Do_I_Find_Former_Employee_Folders_That_Nobody_Owns_Now%3F

Dark data is all the information companies collect but never use—often 60-80% of stored data sits inactive. This hidden stash isn’t just wasting storage space; it can cost businesses up to $2.5 million each year in unnecessary expenses