Impossibly large "Size on disk" reported for my LS420D

[pwaitzman]

I have the file size problem reported by others as well.

My setup = LS420D with 2 2TB drives:
   Disk 1 with 2 shared folders ("MediaServer" & "ActiveWorkFiles"); File System = XFS
   Disk 2 with 1 shared folder ("BackUp" backs up contents in Drive 1 folders weekly); File System = XFS
   I access the NAS with PC's running windows 10

After highlighting the directories in each of the shared folders & each clicking Properties, Windows 10 Explorer reports the following:
   Disk 1:
      "ActiveWorkFIles":
          Size: 78.0 GB (83,818,039,292 bytes)
          Size on disk:  0.97 TB (1,074,949,783,552 bytes)
    "MediaServer":
         Size: 619 GB (665,039,969,681 bytes
         Size on Disk:  3.70 TB (4,074,850,222,080 bytes)
   Disk 2:
      "BackUp":
         Size: 708 GB (760,600,555,179 bytes)
         Size on disk:  5.26 TB (5,788,005,306,368 bytes)

   For both disks, size on disk reported significantly larger than size.
   It is even larger than the disk capacity.

Buffalo NAS Utility reports the following:
   Disk 1 is reported to have 1847.4 GB Unit Capacity with 703.6 GB  (38.09%) Used
   Disk 2 is reported to have 1847.4 GB Unit Capacity with 708.4 GB  (38.35%) Used

It seems that the size on disk is incorrectly reported by Windows 10 Explorer.
Is there a solution for this issue?

[Jerad Whitaker]

This may be a win10 problem.  I have seen Windows report the incorrect size of other external drives (usb sticks, sd cards) as well.