Dark data is all the stored information companies keep but never use—think old...

https://yenkee-wiki.win/index.php/What_Does_%22Data_Stays_Where_It_Lives_Until_Needed%22_Mean_in_Practice%3F

Dark data is all the stored information companies keep but never use—think old files, logs, or emails piling up unnoticed. Surprisingly, 60-80% of data goes untouched, costing businesses around $2.5 million each year in storage and management