Mac mini Late 2012 OS 10.12 Sierra. I recently replaced fusion drive with a 1TB SSD and a 2TB disc Hdd as two separate internal drives. I restored using Time machine Backup from an external drive (which I curiously found to have been formatted Journaled Case Sensitive). I purchased a 5TB Seagate Backup+ Plus Hub external drive. As instructed I formatted it as Mac OS Extended (Journaled) as I usually do to set up a drive for time machine. It has been over 13 hours and it has only backed up 285GB of 1.6TB. I believe that using 3.0 hub should be much quicker. Yesterday after a similar event I stopped the BU and reformatted the drive and started the process over with stated results. Suggestions?