I'm using Windows 10 (version 1803), let's denote my pc user name as
abc. When I right click the folder
c:\users\abc and select Properties, Windows tells me the size of this folder is 16.7 GB.
But when I open this folder
c:\users\abc, select all sub-folders, like
downloads, ... again right click to see properties, Windows now tells me the size is 49.2 GB, which is the actual size.
So why there is so huge the difference? BTW, this problem also happens to my dropbox folder.