Dark data is the information your organization collects but never uses—often...

https://domgodwinson38.gumroad.com/p/what-should-i-do-with-former-employee-folders-on-the-file-server

Dark data is the information your organization collects but never uses—often making up 55% of stored data. This unused data not only wastes money on storage and backup but also increases risk by providing potential entry points for ransomware attacks