Hello, The MAS022 device is the iDRAC7 virtual USB drive.  It is OK to leave it as is.  If it is causing problems, you may perform a soft reboot of the iDRAC7 via the racadm racreset command to try to remove it. Please let us know that works for you. 
Hi after a Firmware and bios upgrade (via lifecycle controller) on an R720, I am noticing a new device in my Device Manager:   MAS022 in "device manager" listed under storage.   How can I make this go away and why does it show up?    
MAS022 in "device manager"