I had the same problem. From what I understand from my research, there is no way to rename it or check the properties (free space) while it's in the Chromebook. Google is working on this.
I had to put mine in my Windows computer and renamed it SanDisk 32G. When I put it back in the Chromebook it showed up with the name SANDISK 32G.
Last edited by booch221; 05-08-2015 at 12:26 PM.