Setting up my new 12'' MacBook and having trouble with any external drives automatically mounting when plugged in. I have tried the new SanDisk Dual USB (A+C) flash drive directly connected via USB-C as well as a WD USB3 hard drive connected with an Apple USB-A to USB-C adapter. Both drives are visible in disk utility, and I can mount them manually just fine, but it seems like those steps shouldn't be required. I have also "verified" and "repaired" them several times even though there are no issues identified. Anybody else have this problem or know of a solution? Thanks.