Unable to use devices repeatedly in same Thunderbolt ports on 2019 MacBook Pro

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Level 1

4 points

Unable to use devices repeatedly in same Thunderbolt ports on 2019 MacBook Pro

I have a 2019 MacBook Pro with 4 Thunderbolt ports. I'm on the latest Sequoia 15.1.1. Over time, these ports seem to 'forget' devices that have been plugged into them, then don't react in any way when they are plugged in again. I have to use a different port before they become recognized and usable. The one that concerns me most is my power cable, because I only have one port left that will work with it, and occasionally, it too forgets. Other devices, such as my external backup drive work on ports that have 'forgotten' my power cable, but those other devices have stopped working on other ports.

Is there any way that I can refresh my ports or connected devices list to get them all working again? Or is this an indication of some damage to the connectors for which I will have to bring it in for repairs?

[Re-Titled by Moderator]

MacBook Pro 16″, macOS 15.1

Posted on Nov 26, 2024 11:19 AM

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Answer 1

Nov 26, 2024 3:42 PM in response to IchabodE

When you eject a USB or ThunderBolt DRIVE, you are correct in that it will not be seen again if plugged in again until after a Restart.

The statement about devices other than drives does not hold true for most users. You SHOULD be able to disconnect and reconnect devices as you wish, and have them reacquired every time.

The behavior of your power adapter, if you have told the COMPLETE story, is Bizarre. However, Readers do find that the Mac latches onto the first available power source, and will generally not switch to another power source, even if a "better" power source is available later.

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Answer 2

HWTech

Level 9

60,740 points

Nov 26, 2024 7:55 PM in response to IchabodE

It is hard to say whether you may have a hardware issue with the laptop. I do know the USB-C ports tend to become damaged from accidental liquid damage....it only takes a small drop of liquid that splashes nearby and the corrosion it forms is not always visible by looking at the ports on the laptop. This is so common with my organization's MBPros, that I try to inspect the ports every time I work on them and if I have to perform a hardware repair for some other reason, then I will remove the I/O Boards to inspect them even if I did not see anything with an external inspection.

Another problem are the USB-C ports can supply power to the laptop as well as carrying data for your devices. This makes these ports much easier to damage by using cheap devices or when an external device fails. In fact, some types of damage/failure with just one USB-C port on the Apple laptop can affect the functionality of the other USB-C port on the same side, or sometimes even affects the ports on the other side of the laptop due to how Apple has the internal circuitry wired.

You can try rotating the USB-C connector on the cable 180º upside down to see if the power adapter or other external device will now work (or if the behavior changes). If the behavior is different, then one of the devices or ports, or cable is half bad.

Also working against you is the much higher failure rate of the Logic Boards on the 2019 models.....especially the 16" model. For this reason, unless the problem is only due to a bad I/O Board on the laptop, then I do not recommend spending any money on repairs as the money spent is better put towards a new laptop.

Have you tried rebooting the laptop to see if the ports work normally for at least one time? I have seen cases where the USB ports can become disabled until after a system reboot.

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