Dark data is the inactive or unused information your company stores but doesn’t...

https://wiki-club.win/index.php/Example_of_Tagging_Research_Files_with_ELN_Project_Codes:_Unlocking_Value_in_Life_Sciences_Data_Management

Dark data is the inactive or unused information your company stores but doesn’t analyze or manage. It can make up 60-80% of your data, leading to wasted storage and backup costs. Plus, it increases your risk of ransomware attacks and data breaches