Dark data is the hidden information your company stores but rarely uses—often...

https://source-wiki.win/index.php/What_Should_I_Track_Monthly_to_Prevent_Dark_Data_from_Creeping_Back%3F

Dark data is the hidden information your company stores but rarely uses—often making up 55% of all data. This idle data can cost millions, create legal risks, and clutter AI projects with irrelevant noise