Computer Management and File Explorer seem to agree on drive C having a total size 20.8 GB with 10.4GB free as shown on the attached graphic. But when the properties of the entire contents of drive C are displayed in File Explorer it shows 17.8GB of data occupying 13.8GB of disk space! (compressed?). These two figures are mutually incompatible as the second must be at least as large as the first and typically larger. The are are both also incompatible with the total size and free space indicated both by Computer Management and File Explorer.
In different windows File Explorer is stating that the total size of the C drive is 20.8GB storing 17.8GB of data in 13.8GB of disk space leaving 10.4GB free!? What am I missing?