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

https://quebeck-wiki.win/index.php/What_Is_Transparent_Move_Technology_and_Why_Do_People_Care%3F

Dark data is the information your company collects but never uses—often 55% of all stored data. Holding onto this inactive data increases storage and backup costs and raises your risk of ransomware or breaches