M4 Mac mini may have a USB-C connectivity problem

Jump to First Reply
Posted:
in Current Mac Hardware

Some M4 Mac mini owners are discovering USB-C issues with their new desktops, with peripherals disconnecting seemingly at random.

A silver Apple device with rounded edges, featuring the Apple logo, positioned on a tiled surface.
M4 Mac mini



USB is a fairly resilient technology, with the expectation that things connected using it will typically remain functional for a very long time, outside of external effects. However, it seems that in a small number of cases, USB-C connections on the M4 Mac mini are problematic.

Various Internet posts uncovered by AppleInsider reveal that users are undergoing similar problems. They generally consist of hardware connected using USB-C suddenly disconnecting and becoming unusable, or not connecting in the first place.

Going down



The reports uncovered in its investigation cover a range of time, ever since the M4 Mac mini's release in late 2024.

In one Reddit example posted on January 15, a poster explains that their USB-C keyboard "intermittently disconnects" and requires a physical disconnect and reconnect to start working again. To rule out other hardware issues, the same keyboard was working fine on the user's other Macs, with the issue only manifesting on the M4 Mac mini.

Other respondents complained that they had similar issues when using docks connecting with USB 3, as well as a KVM switch failing to work after waking the Mac mini. After a physical disconnection and plugging it back in, everything worked fine.

Another said it was only an issue with the rear ports, as the freezes didn't manifest when using the front ports.

A post from the end of December also asked if users had power issues with USB-C devices working off the M4 Mac mini. An external hard drive attached via USB-C disconnected when an "I/O heavy" task was performed, even when directly connected.

Others raised their problems again, with hubs not working with the ports but still working elsewhere. Questions were raised over the power draw of connected devices, as well as whether it was a front or rear USB problem, though it seems not to be limited to the rear set.

Silver computer with rounded edges on a tiled surface, featuring ports and buttons on its front panel.
There are front ports on the new M4 Mac mini



An earlier post from November also brought up a failure in hub connectivity. However, in that instance, the poster said they were using an external power source for the hub instead of relying on bus power.

One respondent in that instance said that their USB-C devices didn't reconnect automatically on their M4 Mac mini, unlike their M1 Mac mini. Again, they had to physically reconnect the devices for them to work.

The issue has also appeared on the Apple Support Forum. One November 23 post explained that the front USB-C ports worked fine, but the rear ports wouldn't work reliably with connected devices, effectively making the rear ports useless.

Replies also included others who had similar problems, with hard drives connecting to USB-C at the front working, but not mounting to the rear.
These signal dropouts can be annoying to users and can be down to a number of reasons.

Elsewhere, the same problem appeared on the MacResource forum, with a user reporting a similar issue. They discovered that the Apple Extended Keyboard didn't work around the back when plugged in via an adapter, but a Logitech mouse plugged in directly worked.

The front ports apparently worked fine in that case.

Puzzling problem



The issue is a difficult one to diagnose, due to the sheer number of variables at play. Since users have complained that it happens when their hardware sleeps, this may also be something that Apple could issue a software update to fix.

Away from Apple, most users may find that they can do a number of checks to make sure it's not a problem they inadvertently caused. Inspecting the cable for damage, including looking for debris in the ports, will help, as well as trying a known-good cable in the setup.

The use of cheap USB-A to USB-C adapters and hubs may also be causing issues, as can poorly constructed cables. Checking these and replacing them if warranted could help the situation for the average user.

There should also be some thought about what devices are connected to which port on a Mac in general. It's not a good idea to have multiple bus-powered devices drawing power from the same single USB-C port on a host Mac.

Something like this could be solved with a powered hub or dock.



Read on AppleInsider

rollo75
«1

Comments

  • Reply 1 of 30
    I have some USB-C speakers I plug into the back of my Mac mini that are doing that.  I noticed it happened mostly when I would use my AirPods in the mornings before everyone got up, and tried to switch back.  Sound would be coming from the Mini and not the speakers.  The only way to fix would be to unplug and replug them in.  I then ran a second USB-C to the speakers PD port to essentially 'power' them, but I still find that it will fall back to the internal speakers at odd times (after sleep, first use in the morning, after using AirPods), but then in the last week, I haven't had any issues.  
    williamlondonAlex1NAlex1Nstevenozwatto_cobra
     1Like 2Dislikes 2Informatives
  • Reply 2 of 30
    Got my M4 Pro Mac mini (64GB Ram,10Gb ethernet and 2TB SSD) two days ago.

    Overnight, Migration Assistant successfully moved everything via WiFi from my M2 Pro Mac mini (32GB Ram, 10GB Ethernet and 2TB SSD) to the new unit. 

    Both units had their own  Magic Keyboard and my Logitech mouse has 3 switchable Bluetooth connections so it worked with both devices. Had to constantly switch the Apple monitor cable for the Studio Display between the two units to get Migration Assistant going. I had the keyboard connected with a Lightning to USB-C cable to one of the M4 Pro front USB-C slots.

    Once done, I added the USB-C cable to the Raid drive to the new mini on the back along with the Studio Display cable. The Logitech mouse and new Magic Keyboard connect vis Bluetooth. I had issues with the Studio Display because I used the prior LG monitor's cable. Putting the Apple Display cable that came with it cured the waking up of the screen issue.

    So far so good. Also SMP and VNC connections over 10Gb ethernet worked where they did not on the prior unit. Both units were on MacOS 15.2 operating system.

    Wondering if the issue with the earlier M4 mini models could be operating system issues if not on latest release? Or, perhaps the issue did not happen with the M4 Pro chip models?
    edited January 15
    williamlondonwatto_cobra
     0Likes 1Dislike 1Informative
  • Reply 3 of 30
    Is USB really a resilient interface? I recently worked a contract where test stations in production would often start reporting errors in the middle of the tests because some of the equipment was connected using USB and it would intermittently disconnect. This is compared to HPIB/GPIB which is old, bulky and slow but extremely robust.
    williamlondondewmeAlex1Nstevenozrezwitswatto_cobra
     5Likes 1Dislike 0Informatives
  • Reply 4 of 30
    Well known (on internet) that Apple wired USB keyboards dont work on the M4 mac mini whereas 3rd party keyboards work. Easily reproducible.
    williamlondonappleinsideruserstevenozrezwitswatto_cobra
     1Like 2Dislikes 2Informatives
  • Reply 5 of 30
    I had an issue with my HooToo USB-C hub failing to connect to my new M4 Pro mini after I had done a cable migration off my 10yo 27"iMac when connected to the rear port only. On the front port it was fine. Several re-boots seemed to fix the issue. It stopped flashing. HooToo hub was bought for my 12" MacBook years ago, which had CPU issues and was scrapped.
    williamlondonwatto_cobra
     1Like 1Dislike 0Informatives
  • Reply 6 of 30
    I had this problem with a hard drive plugged into my Pluggable TS4 dock and one TS4 cable to my M4 Max MacBook Pro. The hard drive would randomly disconnect once in a while. I plugged the hard drive directly into my MacBook and the problem went away.
    williamlondonstevenozwatto_cobra
     1Like 1Dislike 1Informative
  • Reply 7 of 30
    mines worked great so far. I only use the rear ports.
    jas99watto_cobra
     2Likes 0Dislikes 0Informatives
  • Reply 8 of 30
    dewmedewme Posts: 5,873member
    I still have occasional issues with USB ports on different Macs. Usually it’s associated with sleep issues. However I’ve never had any problems with Thunderbolt ports using non-USB protocols like external M.2 SSD enclosures that support PCIe protocol. 
    killroyAlex1Nrezwitswatto_cobra
     4Likes 0Dislikes 0Informatives
  • Reply 9 of 30
    I'm not convinced it's a hardware specific issue. I'm having a similar problem with USB-A and USB-C devices on an older M1 MacBook Air.

    I have had a very stable USB environment using an OWC Thunderbolt 4 Dock (11 port) since 2021. Then right after the latest MacOS 15 upgrade several of my UISB devices lost connectivity. After offloading my USB-A devices to an OWC Thunderbolt 3 mini Dock most came back up but the CyberPower UPS USB-A continues to lose connectivity intermittently.

    So it looks like this is on Apple's software.
    williamlondonforegoneconclusionAlex1Nrezwitswatto_cobra
     1Like 1Dislike 3Informatives
  • Reply 10 of 30
    I once had a 27” aluminium body iMac with this exact problem. Random USB disconnect events affecting any USB attached storage drives. It only manifested itself over extended periods, like an initial time machine backup to an external USB disk. Incremental backups would rarely be affected. Hilariously, I spent ages trying to figure it out myself, to no avail, despite being computer literate and working in the Tech industry. I eventually emailed Steve Jobs about it, and then got great attention from a bunch of people at Apple. They never diagnosed the fault. Eventually, years later, I finally figured it out. I would occasionally get mild electric shocks from the aluminium chassis. I assume this was a design flaw, or some errant connection was being made because something had come loose inside and was making unintended contact within the chassis of the machine. It was some kind of electrical/earthing problem with my iMac. If you read around, USB is apparently quite sensitive to issues like earthing problems. My natural assumption was it was a software fault, but in the end I decided I had been barking up the wrong tree. My guess is this was either a hardware/design problem, or a faulty device off the manufacturing line, and an errant electrical contact was being made which was periodically affecting the operation of the USB bus.
    williamlondondewmeAlex1Nwatto_cobra
     0Likes 1Dislike 3Informatives
  • Reply 11 of 30
    I ordered the M4 pro Mac mini when it was made available in December. I had many odd issues. I had to reload the OS and when issues continued, support had me reload the machine to factory. My Mac would reboot over night for no apparent reason. The only error code pointed to an external drive issue but I didn't have an external drive plugged in. I needed to setup a hard disk with Disk Utility so I could do the first Time Machine. While the HD was formatting, the connection would drop. I tried again and it dropped again. I attributed it to a USB controller issue. I wiped the Mac mini and returned it. I ordered another one a few weeks later. It appears to be working fine. Knock on wood.
    dewmeAlex1Nwatto_cobra
     0Likes 0Dislikes 3Informatives
  • Reply 12 of 30
    dewmedewme Posts: 5,873member
    modeseven said:
    I once had a 27” aluminium body iMac with this exact problem. Random USB disconnect events affecting any USB attached storage drives. It only manifested itself over extended periods, like an initial time machine backup to an external USB disk. Incremental backups would rarely be affected. Hilariously, I spent ages trying to figure it out myself, to no avail, despite being computer literate and working in the Tech industry. I eventually emailed Steve Jobs about it, and then got great attention from a bunch of people at Apple. They never diagnosed the fault. Eventually, years later, I finally figured it out. I would occasionally get mild electric shocks from the aluminium chassis. I assume this was a design flaw, or some errant connection was being made because something had come loose inside and was making unintended contact within the chassis of the machine. It was some kind of electrical/earthing problem with my iMac. If you read around, USB is apparently quite sensitive to issues like earthing problems. My natural assumption was it was a software fault, but in the end I decided I had been barking up the wrong tree. My guess is this was either a hardware/design problem, or a faulty device off the manufacturing line, and an errant electrical contact was being made which was periodically affecting the operation of the USB bus.
    Are you sure the mild electric shocks were not simply static electricity? Once the relative humidity gets below ~35% it’s not uncommon static electricity from your body to discharge to metal objects like your iMac.

     If there were a non-ground electrical connection inside your Mac touching the case of your Mac the power supply’s short circuit protection would cause the Mac to crash.

    USB issues can be very difficult to diagnose at the system level. The best way to troubleshoot USB issues would be to use a hardware USB protocol analyzer/ sniffer. 

    You’d think that Apple would be fully capable of determining whether disconnections are happening inside their machine (hardware, firmware, software) and on the wire. That leaves the external device a mystery but with a protocol analyzer you may be able to find a certain packet or packet sequence that coincides with the failure on the device side. 
    muthuk_vanalingamAlex1Nwatto_cobra
     2Likes 0Dislikes 1Informative
  • Reply 13 of 30
    I’ve been using my base model Mini M4 for over a month.  I’ve successfully attached various external SSD and HDDs to the rear ports without issue.  I currently have an Asus Zenscreen, an Acasis 2.5 dual drive enclosure loaded with two HDD, and an Orico M.2 2TB SSD directly connected to the rear ports.  The Zenscreen and Acasis are both drawing power from the M4, with no issues.  I’m using a USB C hub attached to the front ports for SD card and USB A devices eg, Logitech dongle.  I’ve successfully used both front ports for various connections including Satechi keyboard, adapters, game controllers, card readers.  Fingers crossed the ports will continue to function on this tiny beast.
    jas99foregoneconclusionAlex1Nwatto_cobra
     2Likes 0Dislikes 2Informatives
  • Reply 14 of 30
    dhodho Posts: 1member
    I had to deactivate all sleep and hibernation modes and change the Energy Mode to "High Power". This keeps accessories powered up continuously and avoids most of the issues. 
    dewmesphericAlex1Nwatto_cobra
     1Like 0Dislikes 3Informatives
  • Reply 15 of 30
    Penzipenzi Posts: 29member
    Is USB really a resilient interface? I recently worked a contract where test stations in production would often start reporting errors in the middle of the tests because some of the equipment was connected using USB and it would intermittently disconnect. This is compared to HPIB/GPIB which is old, bulky and slow but extremely robust.
    I have found that USB (and HDMI) are far too flaky in mission critical work, and so I just try to defer to Thunderbolt and DP for as many needs as can be filled by those pieces of tech, despite the increased costs. My peace of mind and smooth workflow are worth it to me. So much so that I try to avoid USB and HDMI even for more regular avenues of life… excepting TVs and consoles, of course.
    jas99Alex1Nwatto_cobra
     3Likes 0Dislikes 0Informatives
  • Reply 16 of 30
    dewmedewme Posts: 5,873member
    Is USB really a resilient interface? I recently worked a contract where test stations in production would often start reporting errors in the middle of the tests because some of the equipment was connected using USB and it would intermittently disconnect. This is compared to HPIB/GPIB which is old, bulky and slow but extremely robust.
    Your gut feel is absolutely correct. GPIB/HPIB is intrinsically more reliable than USB. GPIB (IEEE-488) is a purpose-built parallel bus shared by up to 15 devices, one of which is the dedicated controller. The protocol, signaling, error detection, etc, logic is hardware based and data transfers are deterministic. It was designed for a different purpose than USB was designed for.

    USB is a general purpose serial bus using a host controller (master) that orchestrates all of the communication between up to 127 nodes on each bus, including the controller itself, attached devices and hubs (slaves). Multiple USB busses can be connected together in a tiered topology, with each bus having it’s own controller. USB is not deterministic because communication is scheduled by the master, all devices on a bus share the available bandwidth, and messages are packetized so they must be marshaled and un-marshaled (reassembled) on both ends. However, USB has improved its bandwidth to such a degree since its inception that it can still be used in applications that need very high speed data transfers, e.g., streaming and isochronous control. You could say that in a fixed topology setup USB can be considered to provide bounded determinism, but not absolute determinism. It’s simply doing so much more than GPIB so there are more opportunities for errors.
    jas99Alex1Nrezwitswatto_cobra
     2Likes 0Dislikes 2Informatives
  • Reply 17 of 30
    I don't have this issue with my M4 Mac Mini. I have an old Apple wired keyboard (A1243) with a crappy Dell wired mouse attached to it. The keyboard is then plugged into the front USBC port using a Ugreen USB hub (model:CM478). I have two monitors connected using the rear HDMI and USBC ports.

    I am on Sequoia 15.1. 24Gb RAM and 512Gb storage.

    This is my Energy settings.



    I hope this helps others with their issues.
    edited January 16
    killroyjas99muthuk_vanalingamAlex1Nwatto_cobra
     3Likes 0Dislikes 2Informatives
  • Reply 18 of 30
    Part of an email I sent to initiate a return process for my recently purchased M4 mini: 

    "The device is no use to me as it continually loses peripherals which means multiple times a day I'm juggling port connections. Additionally, several times it's lost both keyboard and mouse and I have to re-start, which is very annoying if I have a number of accounts logged in with different work open."

    Front and back ports, cables verified as good. 
    Alex1Nwatto_cobra
     0Likes 0Dislikes 2Informatives
  • Reply 19 of 30
    After the head scratcher exercise required to use Migration Assistant with one Studio Display and two computers, I connected an external raid via USB-C alongside the Studio Display connection. A 10Gb Ethernet connection goes to my 10Gb hub. The Magic Keyboard and Logitech mouse connect via Bluetooth. Seems okay.

    But my M1 Ultra Mac Studio has suddenly started (after all this time since new with no changes to any
    cables) having resets at night. A new Gremlin to chase down.
    edited January 16
    jas99Alex1Nwatto_cobra
     1Like 0Dislikes 2Informatives
  • Reply 20 of 30
    killroykillroy Posts: 291member
    I wonder if it's the M4 or just the M4 Pro  mini. The M4 Pro has thunderbolt 5   Ii may be a negotiation problem between me older versions and thunderbolt 5.
    edited January 16
    Alex1Nwatto_cobra
     2Likes 0Dislikes 0Informatives
Sign In or Register to comment.