USB hub on Late 2015 iMac

Question

Level 2

331 points

USB hub on Late 2015 iMac

I recently bought a 4K Retina iMac with 16Gb RAM and 1Tb Fusion drive. It is running 10.11.4. Previously I had been using an early 2008 20" iMac also running 10.11.4.

The old iMac has a powered Kensington 7 port hub attached which works just fine on that machine. I had thought to transfer that hub to my new Mac - even though it's only USB 2 it would be fine for my backup drives, printers and scanner.

However, when I connect the hub to the new iMac it is recognised and then almost immediately reset by the Mac which makes it completely useless. The hub still works on my old Mac and also on my Macbook Pro (early 2011).

Does anyone have a suggestion as to how I might make the hub work? Alternatively (since I'll get one in the end anyway) is there a seven port USB 3 hub which is known to work with this model of iMac, which doesn't cost the Earth and is available in the UK. I like the appearance and price of the Orico hub and wonder if it works.

iMac, OS X El Capitan (10.11.4), Late 2015 4K Retina, 16Gb RAM, 1Tb

Posted on Apr 13, 2016 4:17 AM

Reply

Answer 1

Apr 13, 2016 4:59 PM in response to Peter Gaunt

I think the problem is that the USB 2 is not compatible, it needs to be USB3.

However, read this Apple Knowledge Base article and see if it offers additional insight.

OS X El Capitan: If a USB device isn’t working

Reply

Answer 2

DonH49

Level 6

16,716 points

Apr 13, 2016 4:59 PM in response to Peter Gaunt

I'm thinking if you tried a usb hub which connects by usb3 but also has usb2 ports it may work. I use Startech and it works. connects by usb3 but has usb2 ports also. I have three older usb2 devices connected to it. Although it get expensive trying things out.

Reply

Answer 3

rkaufmann87

Level 10

148,642 points

Apr 13, 2016 4:11 PM in response to Peter Gaunt

Personally I am a Belkin USB Hub fan, I agree, get a USB3 hub. Hubs can and do fail, it is very possible your old hub simply is not compatible.

Reply

Answer 4

Peter Gaunt Author

Level 2

331 points

Apr 13, 2016 5:08 PM in response to Peter Gaunt

This is actually more mysterious than it at first looked. Some of my USB devices work on the USB 2 hub and some don't. For example, two of my drives (both identical) work as does my printer and my scanner. One of my drives (a Lacie) doesn't work and neither does my SD card reader (which I no longer need anyway). One of my USB sticks works while the other doesn't. Both work in the USB 3 ports on the back of the iMac and on the USB ports on my wired keyboard. The drives are all USB 3 drives. It's very odd. I can live with this for now I think by shuffling the drives around.

Thanks for all suggestions.

Reply

Answer 5

May 14, 2016 11:58 PM in response to Peter Gaunt

This is something Apple knows about but have provided no solution yet and I its obvious to me they appreciate the problem its causing for their users. Since 10.11 they only support USB 3.0 that is certified against the 2008 usb3.0 v1 spec. You can see this for yourself, connect your usb3.0 hub that is not working properly and go to System Profiler, click on the USB menu, and you will see its listed as a USB2.0 hub not a USB3.0 and I expects its disconnecting or not reading due to the requested current requirement being over the USB2.0 spec. You will find any HUB that is correctly seen as a USB3.0 in system profiler will work properly. I have been tearing my hear out for months with this issue, and I am still looking for a decent 7 or 10 port hub that works, I have a 3 port which is seen properly and it works perfectly.

NicW

Reply

Answer 6

Rudegar

Level 10

182,070 points

May 15, 2016 2:17 AM in response to Peter Gaunt

I have a iMac 2011 and use a wide range of usb hubs both usb2 and usb1.1 and powered and unpowered and hubs connected to other hubs haven't had any problems with el capitan or any of the earlier osx versions I've used

Reply

Answer 7

May 15, 2016 4:21 AM in response to Rudegar

That is not really relevant, this is a definite issue and is known by Apple, there is absolutely not doubt this issue exists.

To see if you are actually affected is quite easy. Connect your USB3.0 Hub, then go into System Profiler, click on the USB menu on the left, then see if your hub is shown as a USB3.0 hub or a USB2.0 hub, if its shown as USB2.0 (which many are) then you will have issues with it disconnecting and being unstable, if you are lucky enough that your particular hub or hubs are all seen as USB3.0 hubs then you will not see any issues.

NicW

Reply

Answer 8

Jul 3, 2016 3:13 PM in response to Peter Gaunt

Not sure if you sorted out the issue, here is what i did.

I have used an Anker 7 USB3 hub forever on a mac mini for a bunch of USB drives (kind of like the design and Anker's support is very very good)

When connecting the hub to my new iMac 27 retina the hub was recognized as a USB2.

I ordered another Anker 7-port USB3 hub but with the same result, recognized as an USB2.

It turned out that both hubs are recognized as USB3 if connected to the USB connector next to the SD card reader, if next to Thunderbolt connector then USB2.

wow

Kenneth

Reply