Hidden file folders?

OK, Spice-mongers, here is another puzzler for you.  I copied four folders with 300 GB of data to a 1 TB hard drive and sent it to a branch office 300 miles away.  The IT contractor on that end installed the drive and I shared it with myself (system administrator with all rights) in an RDP session.  As you can see in the left window, the drive has the 300 GB of data on there.  But in the right window, there is nothing?!  What