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USB ports and Macbook pro 2015

I have a MacBook Pro 2015 with usb 2 ports. My external hard drive had apparently died with no information retrievable. I'm looking for a new External hard drive for my back ups and Time Machine but they all now appear to have usb 3 ports. Do I need a different connector?

MacBook Pro, macOS Sierra (10.12.2)

Posted on Mar 16, 2018 3:21 PM

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4 replies

Mar 16, 2018 4:19 PM in response to applewitch

The ports on the 2015 model are USB-3 capable. Apple has decided NOT to make them blue in color.


Those ports will work fine with USB-3 drives, provided the USB-3 devices are FIRST on the chain (in case of multiple devices on one port), and use the appropriate USB-3 cables, which have another set of conductors deep inside the cable-end. Some (not all) have a Blue insert.


If you previously connected a USB-2 device, occasionally the port gets "stuck" thinking it needs to be a USB-2. A Restart usually sets it straight.

Mar 18, 2018 3:24 PM in response to Grant Bennet-Alder

Grant Bennet-Alder wrote:


Those ports will work fine with USB-3 drives, provided the USB-3 devices are FIRST on the chain (in case of multiple devices on one port), and use the appropriate USB-3 cables, which have another set of conductors deep inside the cable-end. Some (not all) have a Blue insert.


In my experience they have the USB SS (SuperSpeed) logo on the USB-A and micro-B connectors.


Whether or not it has to be "first on the chain" depends on the drive's power demands though. Some all-in-one external hard drive "solutions" need considerably less current than other drives, while USB enclosures might need to account for a worst case. My (bought in 2015) 1 TB Seagate Backup Plus Slim only requests 144 mA when connected directly to a USB 3.0 port. When I connect it to my bus-powered USB 2.0 hub it only requests 100 mA and it works just fine. I don't have a USB 3.0 hub to try it on, although if it's 144 mA it should easily be powered through a bus-powered hub. My USB 3.0 SATA enclosure wants 896 mA and won't work through a bus-powered hub; it won't even show up in System Report. I've also got a Toshiba Canvio USB 3 drive, and that wants 744 mA on a USB 3.0 port. It only requests 400 mA on a USB 2.0 port though.


Of course a "desktop" external drive with its own power supply doesn't care about what power the bus can supply. Maybe a powered hub could help too.

Mar 18, 2018 5:21 PM in response to Grant Bennet-Alder

Grant Bennet-Alder wrote:


I was trying to argue about Speed when setting up a chain of devices. When the Mac sees its first-on-the-chain device as a USB-2 device, it has a tendency to never shift up and try the higher speed for the other devices on the chain.


Your discussion of issues of power draw had never occurred to me. Thanks for chipping in with that.


I thought your were discussing whether or not it would mount at all, where I thought that power/current is the biggest concern. Sometimes it's hard to tell if anything works at all until you try it. That Toshiba drive requests 400 mA on my late-2007 MB (USB 2) but 744 mA on my mid-2012 (USB 3.0). I tried using it on my bus-powered USB 2 hub that can power my Seagate drive but it won't mount even with nothing else connected to the hub.


Right now I like the Seagate as an option because it's the only drive I've tried that says it needs less than 150 mA. That and it has a SATA hard drive inside and not a direct USB interface.

USB ports and Macbook pro 2015

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