Dark data is the information your company collects but never uses—about 55% of...

https://quebeck-wiki.win/index.php/Dark_Data_vs_Cold_Data_%E2%80%93_Are_They_the_Same_Thing%3F

Dark data is the information your company collects but never uses—about 55% of stored data falls into this category. It creates risks like ransomware exposure since unused data often lacks proper security