Dark data is the information companies collect but never use or classify—often...

https://stateofseo.com/how-do-pharma-teams-tag-research-files-with-project-codes/

Dark data is the information companies collect but never use or classify—often 55% of all stored data. This unused data not only racks up storage costs, sometimes wasting over $2.5 million annually, but also creates risks like security gaps