Why Does WinDirStat say that my SSD has used up 90 Gb, but in file explorer it says I've used up 105?

[kennyniu2]

In file explorer, it says C: 13 GB free of 118, but in WinDirStat it says C: 90 GB used
Is there some space being used up somewhere I'm not aware of?

 

[velocityg4]

Did you run it as administrator? Close it. Then right click and run as administrator.