How can I fix USB connection issues on a late 2013 27" iMac

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How can I fix USB connection issues on a late 2013 27" iMac

My external drives keep on disconnecting when plugged into my iMac and when charging an iPhone it gets constantly disconnected and connected. Resetting the SMC didn't help. All ports have the same issue. Can it be corrected through software or can it be improved by changing the USB for newer / better ones?

Otherwise the computer is still really great so I'd have to have to pay a few thousand bucks just to get this solved...

iMac 27″, macOS 10.15

Posted on Jul 7, 2021 3:05 AM

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Answer 1

Top-ranking reply

VikingOSX

Community+ 2024

Level 10

116,795 points

Jul 7, 2021 4:34 AM in response to Robin the wedding photographer

There are four USB-3 ports on that Late-2013 27-inch iMac. They are the latest (and fastest) ports for that model year iMac, and non-replaceable now on a 2013 iMac. Disconnect all but one external drive from these ports, and assess if it still disconnects. If it does, boot into Recovery and run Disk Utility First Aid on that external drive. Hope for a green success indication. Reboot. Eject that disk, and plug in the next external drive, again by itself, repeating the same process as in the first drive. The goal is to ensure that these external drives are no corrupted or damaged.

Observe if one iMac USB port shows more disconnects than other ports, and avoid it if detected.

Consider an inexpensive, powered USB-3 hub that you plug into one of your iMac's USB ports, and then plug your drives into that hub. I never charge my iPhone from the computer ports, preferring to use a compatible power adapter and cable to recharge the phone. Also frees up a USB port too.

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Answer 2

Jul 9, 2021 2:29 PM in response to den.thed

I have only one SSD drive attached and almost never charge the phone on the USB ports because of the continuous disconnection issue, From what I read on other forums the late 2013 iMacs have USB ports that can be unstable.

Having found no other solution, I just ordered

A Thunderbolt hub (3) that'll allow me to attach external USB-C and USB-3 SSDs and other devices into the iMac's Thunderbolt 1 port (using Apple's Thunderbolt 3 to Thunderbolt 2 adapter). Cost around $200-$250. The hub gets it's own power and passes it on to any device that's attached (since the Thunderbolt adapter doesn't pass on bus power). Another cheaper option ($100) is to use a Lacie rugged Thunderbolt external drive and rip out the HDD and replace it with an SSD, but this means that that drive can be plugged into the iMac using Thunderbolt 1 but there will be no reliable USB ports available, so it's not flexible and definitely not future proof.
A 4TB SSD that I'll put into the iMac (that's the largest possible for the 2013 version). This way I don't meed an external SSD as the internal one will be big enough.

On a side note the mouse and a webcam work perfectly in the USB ports, so it could be a power issue.

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Answer 3

Jul 9, 2021 7:17 AM in response to VikingOSX

All ports have the same issue and changing the ssd case didn't help either. So basically there doesn't seem to be any way to fix the USB ports.

I'm going to try and see if I can use the thunderbolt ports to connect external drives..

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Answer 4

den.thed

Level 10

82,564 points

Jul 9, 2021 8:02 AM in response to Robin the wedding photographer

As VikingOSX pointed out, the iMac's USB ports do not have enough power to supply power to multiple portable drives and charge your iPhone at the same time.

You need to be using the wall charger to charge you iPhone or get a Self-Powered USB 3.0 Hub to run more than 3 external buss powered portable USB drives and charge your iPhone at the same time.

For example > https://www.sabrent.com/product/HB-USB30/usb-3-0-4-port-high-powered-hub-4a-power-adapter/

for other examples > https://www.amazon.com/Powered-Usb-Hub/s?k=Powered+Usb+Hub

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How can I fix USB connection issues on a late 2013 27" iMac

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