Dark data is the information companies collect but never use—often sitting idle...

https://wiki-net.win/index.php/How_Do_You_Find_Data_Owners_for_Old_Departmental_Shares%3F

Dark data is the information companies collect but never use—often sitting idle and forgotten. Studies show 60-80% of data falls into this category, leading to wasted storage and security risks. Ignoring dark data can cost businesses up to $2