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Aargh iPhone and iPad won't stay connected to Macbook

Well, predictably, it didn’t work, in fact it made it worse as the Activity Monitor workaround no longer works
 
Edit: more googling found this other option to try, and this has worked for me, though again just temporarily, goes back to disconnecting and reconnecting when I unplug it and plug it in again

Important: If the iPhone plugging and unplugging issue still persists after this, close the Terminal app. Open it one more time and repeat the above steps. This time execute the following command. Instead of the “sudo killall usbd” use: sudo killall -STOP -c usbd (Be careful to write it exactly like this, sudo[space]killall[space]-STOP[space]-c[space] usbd)
Hit “Enter”, provide your Macbook’s Password and hit “Enter” again. This should do the trick. Now, attempt one more time to connect your iPhone to your Mac and see if it works properly!
Click to expand...
 
Yet another edit: it seems this latest workaround actually works until I restart my Mac.. so it's getting there!
 
Okay so Apple's next step was to boot my Mac in safe mode, then see if the issue persists.

So I did, and in safe mode the iPhone is not detected at all - nothing. I plug it in, and zero...
 
Try resetting the location and privacy settings on your iPhone. (ONLY the location and privacy settings NOT all content).

This works for the rapidly connecting and disconnecting issue that iOS devices show every now and then.
 
noorx02 said:
Try resetting the location and privacy settings on your iPhone. (ONLY the location and privacy settings NOT all content).

This works for the rapidly connecting and disconnecting issue that iOS devices show every now and then.
Click to expand...

Hi, that was actually the first thing I tried! :) Sadly no effect...

Just rebooted in normal mode, iPhone is constantly connecting/disconnecting... entered "sudo killall -STOP -c usbd" in Terminal and all okay again

So strange...
 
Oh, then that’s really very odd. Have you tried making a separate user on your Mac and connecting your phone? Or maybe it’s possible it’s a faulty USB port.
 
Okay so Apple's next step was to reset the SMC lol, they sent a guide and now that's done too (though there was no indication that the SMC was reset, but I followed the steps).

I don't think it's a fault USB port - like I say my work iPad connects fine and stays connected.
Not tried the separate user thing yet, will see what Apple comes back with
 
Ok so apples next suggestion was try the test user thing

So I did that, nope, still same. The quest continues.
 
Okay so I’ve just got off the phone after a 45 minute support session with Apple care... he had me do various resets, some I’d already done but some were new, and lo and behold it started working fine using the left hand USB port (right hand one still had the issue but I don’t care so much if ones working).

Even rebooted the machine to check it was still working and yep, all iOS devices connected and stayed connected.

Ended the call, 5 minutes later tried again and the issue is back again on all three iOS devices now

The Air is nearly 7 years old at this point... it has served me very well, but I’m getting a Windows 10 notebook on my next payday.
 
martin2345uk said:
Okay so I’ve just got off the phone after a 45 minute support session with Apple care... he had me do various resets, some I’d already done but some were new, and lo and behold it started working fine using the left hand USB port (right hand one still had the issue but I don’t care so much if ones working).

Even rebooted the machine to check it was still working and yep, all iOS devices connected and stayed connected.

Ended the call, 5 minutes later tried again and the issue is back again on all three iOS devices now

The Air is nearly 7 years old at this point... it has served me very well, but I’m getting a Windows 10 notebook on my next payday.
Click to expand...
It's a shame this didn't work. Weird that we still have the same issue that is very intermittent
 
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Unfortunately it's a software bug that Apple still refuses to acknowledge/fix. I suspect it's the usbd process on the Mac that's causing it but I could be wrong (I'm not a computer programmer).

I have previously worked with AppleCare Mac specialists between August-December 2019 and all they say is it's the USB cable that is causing the issue, despite the SAME cable working with other Macs, power adapters, as well as working with some iPhones plugged into my MacBook using the same cable as normal.

The cables I use have always been the official Apple USB to Lightning Cable and of the 3 cables I have, NONE have any signs of physical damage (i.e. fraying). After Apple replaced these cables, they all seem to work fine for several weeks/months before the same issue starts to happen again, which may suggest that yes the cables are the issue... but it doesn't explain why the same cables work perfectly fine with other Macs, power adapters and with other iPhones connected to my MacBook?

You can read all my troubleshooting steps I've taken with Apple and my investigations into the suspected faulty usbd process here: https://apple.stackexchange.com/que...ction-issue-and-what-does-the-usbd-process-do

However, I will summarise a few things about my investigations with the usbd process:

  • The man page for the usbd process describes it as "usbd allows the system to configure USB iOS devices to charge and to present notifications related to USB devices".
    • So the process only configures USB connections for iOS devices. Thus it should not impact other non-iOS device connections such as an external disk.
  • Killing the usbd process in terminal using the command "sudo killall -STOP -c usbd", pauses the process until you either reboot your Mac or enter the command "sudo killall -CONT -c usbd".
    • So yes, you'll need to reenter this command each time you reboot your Mac and plug in your iPhone. You could probably create some script to prevent the launchdaemon from running it entirely, but I haven't done this (again not a programmer)
  • Reseting privacy settings on the iPhone removes the trust file associated between your Mac and the iPhone which checks if these two devices have been previously trusted to communicate with each other. You can similarly delete the lockdown plist on the Mac by removing the plist in rootless.
    • However unless you comfortable running in rootless, there's not much point as it functions the same way as reseting privacy settings on the iPhone.
    • Neither reseting privacy settings or deleting the lockdown plist fixes the issue
  • From my own investigations fiddling around in terminal/console logs, the only differences I've found with usbd being enabled is that usbd allows your iOS device to charge quicker providing an additional 1600 mA current on top of the USB port's normal specifications of 500 mA.
    • Thus pausing the usbd process will only provide you 500 mA of current (instead of usual 2100 mA), thus your iOS devices will charge considerably slower but provides you a stable connection to communicate between your Mac and iOS devices like syncing and hotspot, etc.
Again, I recommend you read my whole post in Apple Stackexchange (linked above) to see my full list of troubleshooting and all my investigations into the usbd process issue.

If someone has any programming knowledge of what usbd process does or can identify if it's usbd that is causing the issue, I'd appreciate if you can let me know, as this issue is affecting thousands of other users too.

Note, this is my first post on MacRumours, so I apologise if there's any issues with what I've posted above.
 
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