Dark data is all the info your team stores but rarely uses — think old files,...

https://yenkee-wiki.win/index.php/What_Is_%E2%80%9COrphaned_Data%E2%80%9D_and_How_Do_I_Find_It%3F

Dark data is all the info your team stores but rarely uses — think old files, logs, and backups. Around 55% of stored data is “dark,” meaning it just sits there, costing money and storage space