Dark data is the information your company collects but never uses—like old...

https://uniform-wiki.win/index.php/How_Do_I_Get_Visibility_Into_Data_Across_Storage_Silos%3F

Dark data is the information your company collects but never uses—like old files or unused backups. It matters because up to 55% of stored data is dark, leading to wasted storage costs and hidden security risks