Dark data is info stored but never used—think emails, old files, or inactive...

https://www.ready-bookmarks.win/dark-data-is-the-info-companies-collect-but-don-t-use-up-to-55-of-all-data

Dark data is info stored but never used—think emails, old files, or inactive databases. It can make up 55% of a company’s data and often hides risks like security problems or compliance issues