On my newly self built computer I have looked at the properties of my system disk. It's showing: - used space 46.9 GB - free space 884 GB - Capacity 931 GB However when I run a space analyser, called WinDirStat, it shows me that the folders and files on the disk total only 16.0 GB. Why such a huge difference? Just curiosity, really. I'm not short of space. It's not a big problem ... I hope.
Formatting is part of it. The other is how drive manufacturers denote a gigabyte. The technical definition is 1024 MB, but quite commonly manufacturers use 1 GB as equal to 1000 MB. That's going to add up in the terabyte range.
Probably hidden files, like old Windows restore points, take up some space. Try Windows disk cleanup, start and cleanmgr.msc