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iMac 5K and iPhone charging problem

Hi. I have an iMac 5K, and I when I connect an iPhone to the iMac, the charge keeps going on and off constantly! Anyone face the same problem here? It was raised earlier here https://discussions.apple.com/thread/6806292 but with no answer.

iMac Line (2012 and Later)

Posted on Jan 13, 2022 8:18 AM

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Posted on Jan 23, 2022 11:20 AM

Embarrassingly (sheepish face) it seems restarting does help. I also wonder if the issue might be partly to do with having multiple users logged on at once, which this Mac often has. Either way, restarted, with one user logged in, issue seems to go away.

11 replies

Jan 13, 2022 8:29 AM in response to danriverside

Try another Lightning cable and if the problem continues restart as directed below and then restart normally.


Please restart the computer in Safe Mode per the directions in the  How to use safe mode on your Mac - Apple Support link.


Note: If you are using a wireless keyboard please either plug it in using the supplied Lightning cable that shipped with it. If you are using a legacy keyboard or a third-party keyboard that does not have re-charging abilities, please use any USB keyboard. Also note that a Safe Mode restart may require you to hold down the shift key for up to 5 minutes before the computer starts in Safe Mode. You will know it is in Safe Mode when you see “Safe Mode” in the upper right of the display.


Jan 13, 2022 9:44 AM in response to danriverside

Not likely a problem. We are kind of blind here as this is not a widespread issue. So you already restarted in Safe Mode, that is good. Lets do the following and then we can look for obvious issues.


It will help us get a good idea of what is causing your problem if you provide a report of your system, that way we do not have to play 20 questions with you. The report we are requesting does NOT provide any personal information and is extremely safe to use. Please navigate to www.Etrecheck.com and download the free version of EtreCheck. Once you have you downloaded the app and installed it, please run the report and save it.


When you have your report, you can attach it when you reply to this message and we can then review it and help you determine what is needed to get your system running well again.


For instructions on how to download your EtreCheck report and attach it to your reply to this message please click https://discussions.apple.com/docs/DOC-250000211



Jan 14, 2022 11:13 AM in response to danriverside


What I see is the computer has not been restarted in 9 days so that is the first thing to do. Do a normal restart.


Also, there is no indication the computer is being backed up as evidenced by: "No Time Machine backup - Time Machine backup not found." If this is correct this is a MAJOR problem and a 100% guarantee you will lose data. I strongly recommend that you read Back up your Mac with Time Machine which requires an EHD. If you do not have an EHD you can dedicate as a backup EHD many experienced users here use the OWC Mercury Elite Pro.

Jan 14, 2022 11:54 AM in response to danriverside

It's appearing that the problem is hardware related. Don't see anything in the report that would be suspect for this issue. Since the iMac is considered vintage it's questionable that the cost of repair by Apple or an Apple Authorized Service Provider would be warranted.  Using a power adaptor and cable is probably you best solution.


However, it's good to reboot more frequently as that clears out temporary system and app cache and swap files which will help with overall performance.


Also you don't need MemoryCleanHelper. The system's memory management is more than adequate to manage memory allocation and using 3rd party apps is counterproductive.



Jan 13, 2022 9:06 AM in response to rkaufmann87

Thanks for your quick response, but done all that already. It feels to me like there's an issue with the USB charging infrastructure in the iMac, but there doesn't seem to be a recall for it or anything. In the original thread there were a lot of people with the same issue, but no answer was provided.


By the way, this is a problem I've been having for a while and I just stopped trying to charge the phone on the iMac. I can charge Watch OK, just not iPhone. It's on an iMac (Retina 5K, 27-inch, Late 2014).

Jan 14, 2022 11:16 AM in response to rkaufmann87

Thanks, but I can honestly say the restart is not the issue - it's been happening for a long while and I've definitely restarted it many times since I first encountered the issue.


Also, I take the point about the backup, but again I don't think it's relevant to the issue I'm having. I actually have Time Machine backing up to an EHD, but the backup got corrupted recently and it asked me to recreate a backup, which it is in the middle of doing, hence why it can't find one yet


I'm really only interested in the USB charging of iPhone issue, if you can shed any light on that

Jan 14, 2022 11:44 AM in response to danriverside

I don't see anything in the report that indicates a problem. You are correct about the backup, that has nothing to do with the issue you asked about however it should be a high priority issue you should address as all of your data is at risk.


The fact that you have not restarted in 9 days indicates you did not restart in Safe Mode so you need to do that first and then restart normally and then retest for the problem. This takes less than 10 minutes to do and should be done first before looking for anything else.

iMac 5K and iPhone charging problem

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