iPhone connects and disconnects from Mac

Further testing shows that just force quitting USBD from Activity Monitor only works temporarily. Once phone is disconnected and then reconnected, the problem returns. But you can resolve this issue more permanently, by using this terminal command whilst phone is connected via USB:

sudo killall -STOP -c usbd

This should be fine until you update OS.

Now all that remains is the annoying "Trust this computer?" alert every time I plug phone in...

This is infuriating! I am doing a video project and I cant get my videos off of my iphone. tried all of the suggestions here. Im paying good money for this phone. Iphone Xr, 2016 macbook pro. Apple you get so much of my money. Im over it. Fix your crap apple. its become junk. outrageous. LEAVE APPLE PPL

After trying all of these and having some temporary success, this seems to have worked, but I won't really believe it for a few days when I see if it comes back or not. But so far, so good. I did have to manually enter the IP address, which I copied from the Wifi information on the Network screen. Crossing my fingers.

This solution did the trick for me. iPhone 7 and Macbook Pro, both with the latest version IOS13. My battery charging is still a little wonky, but I am happy that Photos is not opening and closing in an endless loop! Thanks.....la3

Spent three days at the Apple store. Finally a tech deleted my phone backups and created a new one and that's all it seemed to take. Maybe it was some other things we'd tried previously, but this seemed to work right away. There seemed to be some conflict with iTunes and Photos bumping into each when I connected. I know it sounds too easy, but give it a try. It worked for me.

Update:

The problem persists, albeit seemingly less severe. The iPhone doesn't connect and disconnect as viciously as before and after a few back and forths, it stops. But, I still have to open terminal and enter that command for it to calm down.

I should note that I tried deleting all the backups on my computer as well as deactivating Photos from automatically opening (because mentioned in previous comments as helpful).

Result:

Solution did not work. Problem persists.

That is genius Arashk B. It’s a very frustrating problem that a lot of people are experiencing. Using my troubleshooting abilities developed through years of computer programming I had arrived at the same conclusion. I had determined that it’s a software based problem because the lightning cables that people are using are working everywhere else and the USB ports on their MacBooks are working with other USB devices. So there’s a bug in the OS (or it’s written that way) so when the power is low on the attached USB device MacOs will automatically send a disconnect to the USB port. Then the OS does what it was designed to do: it detects there’s something in the USB port and connects again! I’m communicating through Apple and some of my IOS app developers to see if there’s a work around.

This has happened to me so many times and I could never pinpoint the variables until this super helpful post! Thank you to all that have weighed in on this.

Here's what consistently works for me nowadays with my iphone7. If my phone is charged above 50% and my phone disconnects, then I need to delete the "usbd" process from the Activity Monitor on the receiving computer. If my phone is charged below 50% (and that battery indicator is not always that accurate), then charging my phone works. I did not realize that the power level on my phone would make a difference, but it does.

Thanks mate, it works for me! However after disconnecting the phone the problem come back. I re-done it and back to works again.

Do you know why this started to happen in the first place? I used it for many years with my old Iphone 8 plus but just started after I upgraded to Iphone 11 pro.

Yes, it worked! With one extra step -- My iPhone kept asking if I should trust the computer: the alert box kept popping up and disappearing as the phone repeatedly connected and disconnected from the computer. Be quick! As soon as you see the alert on your phone, click Trust. Worked for me. Thanks, Welibekov!

I also am having this issue when connecting both my iPad Mini 4 and iPhone XS, and killing the usbd process on my Macbook Pro also solves it.

But here's an unexpected twist: I only see the problem when using the lightning cables from those devices. If I use a lightning cable from my iPhone 6, it works fine every time, without having to kill the usbd process.

Can anyone else reproduce that? If so, maybe it's being caused by a characteristic of newer lightning cables?

I am having same issue with iPhone XR rapidly connecting and disconnecting when I plug it via USB into my MacBook Pro (Retina, 15-inch, Mid 2015).

It is interesting to read about all of the solutions that worked, worked only once (or sometimes) or not at all.

It seems like there is not a definite solution that would work for everybody.

Someone mentioned that we pay a lot of money to Apple for their products. So true. We make them soooo rich !!!

So in return, we all deserve things to work together without the problems we're experiencing and that make us scratch our heads and waste our time trying to fix these problems.

At one of his famous keynotes, Steve Jobs said: "It Just Works".

That's what we pay for, that's what we expect and that's what you, Apple, need to get back to.

So Apple folks, please figure this problem out and give us the proper fix.

Thank you,

Bronco Hyrman

Apple User since 1994

Worked for me. So far so good and my iphone XS Max (using on my 2015 Macbook Air) quit connecting then disconnecting repeatedly. Was literally sitting here doing it over and over and over. Hasnt done it in about 10 min now. If anything changes, i will be sure to update. Thank you so much

I had the EXACT SAME ISSUE!!

Open iTunes on your MacBook,

click the “ITunes” option on the task bar (too right side of screen)

Preferences > Devices > then uncheck “Prevent iPhones from syncing”

Now just plug in your device and trust your MacBook !!

Abra!! Kadabra!!

In addition to what others have stated - I have had a couple of my laptops usb port get slightly loose and basically go out one didn't get loose and would not work for almost every usb device plugged into it but would on one or two... my other port worked continually for the life of those computers. SEE if it's in there firmly, try another usb port like a battery pac - and also consider the cords DO go out, even if new - I recently had two new ones go out - one after a few days and another after a few weeks.