How can I fix USB4 port recognition issues on my Mac mini?

AntonyFromWatertown wrote:

I have a 2001 iMac M1, running Sequoia. I have had many problems using the USB 4 ports on this computer. My iMac has 2 USB 4 ports, and 2 Thunderbolt ports.

All variants of the 24" M1 iMac have two Thunderbolt / USB4 ports, with USB-C connectors, which support multiple protocols. Some variants have two additional USB-C ports which support USB 3.* only. Those ports do not support the newer USB4 standard.

iMac (24-inch, M1, 2021) - Technical Specifications - Apple Support

My Apple USB 2 extended keyboard was not recognized by either the USB 4 ports, or the Thunderbolt ports, using an Insignia USB 3 to 4 adapter.

I've never heard of a "USB 3 to 4 adapter". Do you mean a USB-C to USB-A adapter?

If the keyboard is not recognized on of the ports, but other USB 2/3 devices work on at least some of those ports, that might suggest that the keyboard is malfunctioning, or that Apple removed support for it from macOS.

Currently, that keyboard is connected through an Insignia 3-port adapter that has 1 USB 3 port (which has the keyboard), 1 HDMI port, and 1 Thunderbolt port. That adapter is using a Thunderbolt port.

I don't see any Insignia Thunderbolt-based hubs, docks, or adapters on the Best Buy site. There is an Insignia™ USB-C to HDMI Multiport Adapter . This device no doubt expects to see both a DisplayPort Alt Mode signal (only available on the iMac's USB4 / Thunderbolt ports) and a USB 3 one. It knows nothing of Thunderbolt or of USB4.

The USB-C port on that adapter seems to be for plugging in an external USB-C power brick. If you were using the adapter with a Mac notebook, you could plug the power brick into the adapter, and the adapter would pass power along to the notebook over the same USB-C connection that carried video and USB data. Since you are using an iMac that has its own power supply, this port is basically useless. You don't need it for power, and it doesn't have (as far as I can tell) the ability to carry data.

Nothing that I have will work on the USB 4 ports on the iMac.

If you mean that no USB 2 or USB 3 devices work with the USB 3 ports, that might suggest either

• That you were using "charging" cables that only connected 5V power pins, not data pins; or
• That there is a hardware problem with the iMac's USB 3 ports.

USB 2 and 3 devices should work with any your iMac's four USB-C ports, although it may be desirable to try to keep the USB4 / Thunderbolt ports available for devices that need the extra capabilities that only those ports possess.

Sorry, your post is a bit confusing.

If I'm understanding correctly, the docks and adapters you have don't work when connected through the regular USB-C ports but work when connected to the thunderbolt ports.

AntonyFromWatertown wrote:

Currently, that keyboard is connected through an Insignia 3-port adapter that has 1 USB 3 port (which has the keyboard), 1 HDMI port, and 1 Thunderbolt port

This seems like its a Thunderbolt dock, which will not work through the regular USB-C ports, since it requires a thunderbolt signal. The regular USB-C ports don't produce this signal so the dock will not work.

The other hubs may also be expecting a thunderbolt signal rather than just USB.

an Insignia USB 3 to 4 adapter.

This for instance is likely a Thunderbolt 3/4 to USB adapter, again requiring a thunderbolt signal from the computer, which is why it would not work through the regular USB-C ports. It's not common for anyone to call out USB 3 or USB 4 in adapters. Generally they are just USB to USB-C.

Some adapters may mention they are Thunderbolt 3/4 which still uses the same USB-C port for both thunderbolt types, so an adapter for that is not required.

I think you are trying to use Thunderbolt adapters and docks on the USB-C ports and that will not work.

If you can identify exactly what adapters and hubs you are using we may be able to determine if that is the case.

[Edited by Moderator]

AntonyFromWatertown wrote:

Another problem that I am having (which led to my current one) is that I have two external USB 3 drives currently connected through a USB 3 hub and an adapter to a thunderbolt port. Both are 8TB. One is used for file storage, the other is for Time Machine. Recently, both drives have been experiencing connectivity problems. They drop offline at random intervals, not related to anything that I am doing.

Have you been putting the Mac to Sleep?

If so, avoid doing that. Use Lock Screen, and let the computer blank the screen or run a screensaver, if you like, but don't put the whole machine to Sleep. That seems to be associated with unwanted drive disconnections.

USB 3 is a protocol that runs on many kinds of USB connectors. Not just USB-A, but also on USB 3.0 B, USB 3.0 Micro B, and USB-C. It’s simply that people associate it with USB-A connectors because, outside of printers and portable drives, USB-A had by far the widest use.

That should work with all the ports. What happens when you plug that adapter into the iMac, and then the keyboard into the adapter.