2.5 years later, I upgrade my rating from 2 stars to 5 stars!
I bought the Sabrent ED-DFLT enclosure so that I could format various hard drives on my iMac. It's a rather long story, which I'll shorten to this: I confirmed that the Sabrent enclosure worked when I received it by using an old 2TB drive. I then tossed the box and waited for my 6TB Western Digital Caviar Green drive to arrive from Amazon a couple of weeks later. When plopped into the Sabrent, the new drive showed up on my Mac's desktop. I then set about creating a large encrypted disk image on the drive. It chugged away for 4 full days, seemingly working for the first 3. But after day 4, the formatting was clearly hung, and it had taken my Mac down with it. Upon rebooting, the drive no longer showed up at all. Disk Utility could not even see it. After a lot of detective work, too long to describe here, I confirmed that the 6TB drive was still working fine, but the Sabrent logic board had died, obviously a case of infant mortality. The good news: it can handle large capacity hard drives. The bad news: not for very long... And of course, since I tossed the boxing, there is no returning the Sabrent. I therefore spent $23 on a brick, although it won't break me. This case of infant mortality is probably just a fluke, but an annoying one when it happens to you. I should have kept the box a while longer. My bad. UPDATE 1/2118: To Sabrent's great credit, and this is going back about 2.5 years ago, they stepped in and replaced the enclosure, no charge. I tested it but ran into issues trying to do the above formatting again, and threw it on my junk pile. With hindsight, I'm now realizing that the issue was most likely the hard drive I was using, which I got by ripping open a Western Digital external hard drive and removing it. There's something odd about the firmware in these drives. They're just "not right" when taken out of their manufacturer's shell and fully exposed like this. I think my issue was the hard drive, and NOT Sabrent. Coupled with their excellent customer service, I've now increased the rating to five stars. Because ... I just bought some 8TB Hitachi hard drives and it was time to format them, again with encryption. These are new, bare hard drives from Amazon, not something I ripped out of an external HD box! Fortunately, I still had the Sabrent enclosure, so I pulled one off the pile, attached the 12V/1.5A power adapter to it, put the 8TB drive in, connected to my Mac Mini, and just like that, the hard drive mounted on the desktop. I formatted it in HFS+, then created a new encrypted disk image, and let it run. This time, all went well. I discovered that if you open Sierra's Activity Monitor and click on Disk Activity, you get a readout of how fast the data is moving across the interface. I was seeing it move between 110 - 160 MB/sec, averaging about 130 MB/sec. That's not bad at all on my 2012 iMac with a 4-core i7 processor running Sierra (12.6). It's not the fastest i7 there is, so you have to remember that there are calculations that first have to be made before the data can be spit out of the USB3 ports for writing. That takes time to execute, which has to slow transfers down somewhat. USB of any speed never hits its theoretical maximum anyway (4.8Gbps for USB3, or about 600 MB/sec). Considering I was getting only 25 MB/sec with USB2 on this same machine (theoretical maximum speed = 60 MB/sec), actual speeds are less than theoretical speeds by about the same factor for each version of USB. The full 8TB of writing took 17 hours, which averages out to 130 MB/sec, consistent with what I see in Activity Monitor. I would say that's pretty good. I'm happy. Side note: I got to wondering about Sabrent's advice to run a firmware update. I'm a Mac guy, but I have an old PC running XP. I thought I would take a stab at the upgrade. I downloaded it to the PC, but the update would not run at all. You tell it to RUN the update and nothing happens. My neighbor has a PC running Windows 10, so I took the dock, power supply, and a USB cable to his place. He downloaded the update to his PC, followed the .pdf instructions exactly, the interface presented is NOT what the .pdf shows, but tried running it anyway. Same issue: hit the RUN button and nothing happens. It doesn't freeze or anything like that. It simply does nothing. So much for that! The key point I'm making is that this same dock that I bought 2.5 years ago (August 2015) easily sees my 8TB drives, runs flawlessly, and runs quite fast, all with no firmware update whatsoever. I don't understand Sabrent's statement that older docks (2.5 years old?) without an update are limited to 4TB. Not mine! I do not understand why other commenters can't get it to work right. It works perfectly for me. Considering Sabrent's great customer support, excellent USB3 performance, full support for an 8TB drive, and it's very low price, I gotta give it 5 stars! UPDATE 1/30/2018: Plugging into two different iMacs running Snow Leopard (10.6.8), neither can see any drive plugged into it. Odd, since at one time it could/did. I don't know what the difference is, but if you're running Snow Leopard, you might consider passing on the Sabrent. UPDATE 2/12/2018: Okay, so the Sabrent isn't happy with Snow Leopard. Separately, I plugged the Sabrent into my 2012 Mac Mini w/i7 processor and running Sierra (12.6). I plugged a second, different external USB3 drive enclosure to another port, loaded a pair of 8TB X300 Toshiba hard drives in each, and proceeded to move data from one drive to the other. Measured speed is about 130 MB/sec, which is about max transfer rates that these hard drives can deliver. No complaints! Read more