I'm having a bizarre issue with my rMB, every now and then it doesn't recognize external drives, whether it's a flash drive, hard drive or an optical drive. It does this with both my USB-C hub (http://amzn.to/2b1kB2g) and my USB-C adapters (http://amzn.to/2aPuNi1), and the only way to totally fix it is to do a restart (and of course it wears off after a while). Is anyone else having the same issue? EDIT: Updating to Sierra totally resolved this problem, I've been on Sierra for a week as of this edit and my external drives get recognized every single time as they should be. Glad that Apple squashed this bug flat.