Hidden folder in Robocopy

I'm trying to backup a hard drive with two partitions on it to another drive with only one partition using Robocopy. I am running my commands in PowerShell.

The source drive is a USB2.0 drive and the other drive is a USB3.0.My volumes are as listed:

• Wolverine  F:\   NTFS    is my destination drive
• Oriskany  G:\   FAT32   one of the two source drives
• Essex     H:\   NTFS    second of the two source drives

I'm using the commands

robocopy H:\ F:\Essex\    /MIR /Erobocopy G:\ F:\Oriskany\ /MIR /E

I ran the "Oriskany" command first and had no problem;all data showed up -- about 17GB worth.The problem occurs when I try to run the command for Essex (213GB). Even if I create the folder before running the command, the folder Essex disappears during running. The data is still there but the only way to get to the folder is to type in "F:\Essex" to open the folder. I checked if it was hidden and it isn't a hidden object so I have no clue what it is.

So what am I doing wrong? I am rather new to command line.