Dark data is information your business collects and stores but doesn’t use—up...

https://echo-wiki.win/index.php/How_Do_I_Find_Unknown_Departmental_Shares_That_Nobody_Owns%3F

Dark data is information your business collects and stores but doesn’t use—up to 55% of all data. This can increase your risk of ransomware attacks and data breaches since you’re unknowingly exposing unused files