I'm a fairly new, enthusiastic, user of MC. Thank You!
One difference I've seen between MC and my previous explorer substitute (xplorer2) is that in MC my Android phone (Nexus 5 - Marshmallow) doesn't show up to allow file transfers whereas in Explorer and xplorer2 the phone does.
I found a 2013 post in these forums that states only items with volume letters can be displayed. I'd urge doing what xplorer2 has somehow accomplished, making USB attached devices visible, at least as an option.