I've been backing up my system on an external drive for years. I'm currently using Windows 7, 64-bit environment.
In using WinDirStat, I wanted to determine if there was redundancy so I can delete certain files. The result was that I found 180GB of data that are not accessible, viewable, or even visible to Windows Explorer.
I would like to know what this data is, but the main objective is to get rid of it so I can clear up 180GB of room on my disk drive before doing a complete back up again. I've tried several ways to delete it, but each has been unsuccessful. What can I do?
Thank you for your help.