Slow Sync between iPhone & Computer

Such problem troubled me since the update of iTunes 12.7.4 few days ago. I spent 10+ hrs to wait for the completion of iPhone/iPad sync but it was ended by terminating the sync or force close of iTunes itself.

I tried to uninstall the iTunes and reinstall it, but this doesn’t help. I eventually uninstall the version 12.7.4 then reinstall the last version 12.7.3, I then retrieve the iTunes Library that matches the version 12.7.3 from the backup folder, the captioned problem solved.

I think the very slow sync problem should be caused by the new iTunes, I don't know why Apple always release the buggy stuff to users. I am sure no Apple user is willing to spend time for troubleshooting the new release of the software or iOS. I don’t except to have fantastic functions while receiving such updates, I just want the updates are less bugs than before. Apple, please offer us a better management of software release. Where are your software engineers? Where are your testers/QC guys?

When you delete iTunes for troubleshooting, there is an important driver left behind that should be removed as well. Try deleting iTunes once again, but also remove "Apple Mobile Device Support" (also in Control Panel's list of Programs). When you reinstall iTunes, AMDS is also installed.

You might also try a new Lightning cable to see if that helps.

I have found that the amount of time it takes in the "Reading photos from <location>" step depends on how many images are in the "iPod Photo Cache" folder. This suggests a partial workaround:

1) Select all the photos you want to sync in a single batch.

2) Delete the "iPod Photo Cache" folder.

3) Do the sync.

That will remove all the photos that you're syncing and recopy them all; but at least that will take only a few hours instead of a few days.

I have contacted Apple Support about this, and they escalated me to a higher-level support person; so maybe I'll have more information to report in a week or so.

At least they've sort of acknowledged it, which is something. This is the frustration with Apple's support structure; they're very good at face-to-face and phone support when dealing with known or widespread issues (or user error!) but not so great at the deeper technical stuff, at least not until a threshold is reached. And of course we often don't know what that threshold is, or if it's reached, because there's little or no feedback on direct bug reports. Only through users like yourself, who have taken the time to engage with Support over a prolonged period, do we get even a hint of what's happening. Quite often I've seen bugs fixed long before anyone from Apple even acknowledges that they were there in the first place.

To some extent I do understand why they do this; if the same priority was assigned to every entitled cry of "Something broke," they'd drown in the noise. But it's frustrating to see so many threads on here and elsewhere, with posts from clearly technically literate users, effectively not achieving anything. And this particular bug is probably something so simple -- like a "don't repeat this if already done" flag not getting set properly -- that it may be a relatively trivial fix once they can reproduce it.

For what it's worth I've rolled my iTunes back to 12.7.3.46 until Apple can fix this, and now everything is speedy again. "Reading photos from..." takes between 16 and 30 seconds for my 6000+ photo library depending on how many I'm adding, and iOS 11.4pb2 has cured the timeouts I was getting on the iPad.

It's made Photos usable again. Let's hope there are no unfortunate consequences to the temporary rollback.

iTunes 12.7.5, just released simultaneously with iOS 11.4, appears to solve the problem. It does not seem to be necessary to upgrade to iOS 11.4 to solve it -- rather, the problem appears to be in iTunes rather than in iOS.

It would probably be a good idea to remove the "iPod Photo Cache" folder completely from your pictures folder before trying the sync again, on the basis that the cache might have been corrupted by the prior bug.

I faced the same issue over the last week. Yesterday I upgraded iTunes to 12.7.5. It's now working (for the time being) for both iPhone & iPad. The issue appears to be with iTunes not iOS. I'm crossing fingers. I had faced similar issues in September last year. Thanks & regards, Hubert.

Thanks for the information in you posts it does sum up what I was seeing.

Even using a fast Z370 PC with M.2 SSD disk I saw as slow as 1 photo per sec on a second re-sync.

Windows 7 or 10 Resource monitor will also let you see how slow the process is going.

I use many Mac and Windows computers with itunes to hold my work pictures and need sync to keep different parts on different iPads. Windows iTunes was a little easier for splitting up projects.

As you found out reverting back to iTunes 12.7.3.46 seems the best solution for now.

I do not see any place in the Apple developer forum for reporting Windows itunes problems.

I basically agree with everything denali_uk said with one exception:

"This is why the old trick of deleting the iPod Photo Cache appears to "cure" the problem; with no cache folder for comparison, iTunes gets straight down to the task of recreating it while copying all of the photos to the device. But the end result is no faster. All that is happening is that iTunes is recreating the cache (with visible feedback, because it's also copying files to the device) rather than comparing the existing one in silence with no feedback."

My experience is totally different from this. If I delete the iPod Photo Cache and then sync 6,000 files, it takes about an hour. If I then try exactly the same sync again, which should copy no files at all, it takes TWO DAYS.

In other words, when there are a lot of files in the cache, iTunes spends much more time examining the files in the cache than it does recreating them if they are not there in the first place.

I just posted this to another thread:

Re: The ipad cannot be synced. An internal device error occurred.

TL;DR: the latest iOS 11.4 public beta seems to have cured my iPad crashing/sync stopping problem, but not the long-standing "Reading photos..." delay while the cache is checked. I'll have to keep deleting the cache prior to every sync, to keep the wasted time to a minimum.

If there are any further relevant revelations I'll post them here.

Same issue here on Windows 10 FCU (Dell XPS 15), iPhone X (11.3) and iTunes 12.7.4.80.

With about 65,000 photos/videos I had to cancel the sync after about 20 hours (I can only leave my phone plugged in for sooo long before needing to go somewhere).

Used to take about 10 minutes to sync when I added a new folder to the sync list.

Now (new iTunes and iOS so not sure which is causing the problem but suspect it has to be iTunes) I cannot sync anywhere close to all of my photos due to the time involved.

Troubleshooting steps so far:

- remove iTunes and all other "Apple" software (Bonjour, device support, etc.) from Programs

- reinstall iTunes (new download)

- run iTunes as "administrator"

- delete "iPod Photo Cache" folder

- modify thread priority of associated programs from low to normal

- switch photo sync to iCloud (to clear all photos on device) and back to iTunes

I was thinking that maybe iTunes was creating HEIF thumbnails to replace the older JPGs but the .ithumb files are clearly still JPG encoding. CPU sits at ~25% when computer is active and ~40% when inactive (screen off, power saving). No progress indicator, nothing. If I choose to sync only 5000 photos it /does/ complete after about 5 hours - but I have to have the ability to sync more than this.

So frustrated that a process that has worked perfectly for me since my iPhone 3G has all of a sudden caused such a ridiculous headache with no solution in sight! Since I can't move to iCloud (due to bandwidth issues) I will be investigating other solutions such as Google Photos. Anyone have recommendations on alternatives to Apple Photos and iTunes to sync directly from PC?

Run iTunes as admin, fixes sync issue.

FWIW, the Apple rep who has been working with me on this issue said that the developers are starting to get multiple reports of this problem, so there is at least a chance that it will be fixed in a few months or so.

I'm posting to report success after the update also, though I was getting an error message at first. After a restart and clearing out the iPod Photo Cache more than once, it finally worked.

FWIW I was also able to re-enable my iCloud music library within iTunes, which had also stopped working.