Dark data is the information companies collect but don’t use—like old files or...

https://wiki-view.win/index.php/Why_Do_RAG_Systems_Hallucinate_with_Messy_Enterprise_Data%3F

Dark data is the information companies collect but don’t use—like old files or unused emails. It can be a big problem because 55% of stored data falls into this category, leading to wasted storage costs and security risks