You can make a difference in the Apple Support Community!

When you sign up with your Apple Account, you can provide valuable feedback to other community members by upvoting helpful replies and User Tips.

Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

Constant syncing problems with iPhone and Big Sur

I've had this problem for at least the last three versions of Mac OS. My iPhone gets stuck either in

"waiting for sync to start" or even before that, where the progress bar is greyed out and it won't even begin to sync. Please do not simply tell me to update IOS and Mac OS. I've done that. It does not help. I usually have to reboot repeatedly and power off the iPhone, and restart the Finder until it will finally work.

The other problem is when i want to shut down and Mac OS won't let me do it because there's a sync operation in progress . . . which is stuck in the aforementioned "waiting for sync to start." I usually have to resort to holding in the power button to shut down. I know that's not good, but there's no other way to get out of this.

Please fix this!!! I've had it for multiple versions of IOS and Mac OS. I'm getting tired of it.

Posted on Dec 11, 2020 9:26 PM

Reply
Question marked as Top-ranking reply

Posted on Feb 25, 2021 1:32 AM

Hey folks!


Unplug the cable to stop the repeated connecting and disconnecting behavior. If you don’t do it, the iPhone will warm-up and this surly doesn’t help battery ageing. Next, proceed as follows:


  • Open the Finder app.
  • Use its Search function, top-right corner and type Terminal.
  • Copy/paste the following command in the Terminal window:
  • sudo killall -STOP -c usbd
  • Important: Make sure that the text is typed exactly as underlined above, maintaining the spaces.
  • Press the Return key to run the command!


That’s it, your iPhone should be now able to connect to your Mac without any problem


Cheers

Drew

6 replies
Question marked as Top-ranking reply

Feb 25, 2021 1:32 AM in response to logres

Hey folks!


Unplug the cable to stop the repeated connecting and disconnecting behavior. If you don’t do it, the iPhone will warm-up and this surly doesn’t help battery ageing. Next, proceed as follows:


  • Open the Finder app.
  • Use its Search function, top-right corner and type Terminal.
  • Copy/paste the following command in the Terminal window:
  • sudo killall -STOP -c usbd
  • Important: Make sure that the text is typed exactly as underlined above, maintaining the spaces.
  • Press the Return key to run the command!


That’s it, your iPhone should be now able to connect to your Mac without any problem


Cheers

Drew

Dec 11, 2020 9:30 PM in response to logres

I should just add that there should be a way to eject the iPhone when this is happening, and there doesn't seem to be. This happens whether or not I am connected via the cable or syncing over WiFi. Even when I power down the iPhone, it is still stuck trying to sync, and that's when I have to force the iMac to shut down.

Jan 3, 2021 12:26 AM in response to logres

For what little help it may be, I find that right-clicking the device under locations gives me an eject option that works. Then it's a reboot of the device and a forced restart of finder so I can connect by cable at least once - after which wifi sync will work again.

Not sure, but it seems like it breaks every time either end gets an update.

Constant syncing problems with iPhone and Big Sur

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.