An Unexpected Fix for an iPad Syncing Error
I don’t sync my iPad all too often. It holds a charge for so long and is nearly always on a Wi-Fi network, so it’s easy to just plug it in at night, download app updates directly on the device, and forget that it can even sync with iTunes at all.
So when I have a lot of new music or other media to sync, the process can take a while. iTunes inevitably wants to back up the device—which I appreciate—and make sure everything’s in order. Recently, though, I began to encounter a decidedly unpleasant issue when syncing: an ambiguous error was halting the syncing process prematurely. Again and again, each time I tried to sync, iTunes popped up this error:
“The iPad ‘Lex’s iPad’ cannot be synced. The required file cannot be found.”
To my eyes, that error message has two defining characteristics:
- It’s not in the slightest bit helpful.
- It seems highly Google-able.
So I searched the Internet for a fix. As it turns out, the true culprit for this poorly described error is, of all things, iPhoto. Apple has a rather terse support note, “Issues when syncing photos to iPhone or iPod touch,” that gave me the clue I needed to fix the problem.
When you sync photos to your iOS devices, iTunes creates a hidden folder called iPod Photo Cache. That’s where it tucks away data regarding your photos to optimize them for your iPhones, iPod touches, and iPads.
The fix? Delete the iPod Photo Cache folder.
To find the folder, first quit iPhoto and then navigate to your iPhoto Library, which is located in your home folder at
~/Pictures/iPhoto Library. When you find it, Control-click it and choose Show Package Contents from the contextual menu. (The iPhoto Library is a package, which is a special sort of folder. Show Package Contents exposes its contents.)
Inside that folder, you’ll find the iPod Photo Cache folder. Drag it to the Trash. (If you don’t make regular backups—well, first, shame on you, but second, you may prefer just to drag the iPod Photo Cache to the Desktop, and not trash it right away. But the fact that iTunes can easily regenerate the cache is at the core of this fix.)
It’s also worth noting that the iPod Photo Cache can contain a lot of unnecessary data; Adam Engst was having the same problem syncing his iPad, and his iPod Photo Cache folder weighed in at over 11 GB when he deleted it; the regenerated copy took up less than 2 GB. If you switch from syncing photos from iPhoto to syncing from another folder, you’ll want to remove the folder manually to recover disk space—see Apple’s “iTunes: Photo sync creates iPod Photo Cache folder” support note.
Once you’ve axed the iPod Photo Cache folder, relaunch iTunes. Attach your iPad to your Mac, click its name in the sidebar, and then click the Photos button in the main iTunes pane. You need to reconfigure which albums, events, and faces you wish to sync, and when you’re done, click the Apply button to sync your iPad. You’ll see a warning that photos on the iPad will be replaced; don’t worry about it, since all the photos that are being replaced came from your Mac to start with. The sync should proceed apace (though iTunes has to optimize all your photos again, so it may take a little while), but when it’s done, rejoice: the error message will be a thing of the past.
I don’t yet understand why or when this error occurs, or how to prevent it. But the workaround is painless enough, and recurrence of the error rare enough, that I haven’t given it much thought.
I have noticed that iTunes can create a damaged picture file in the ipod cache if you are editing the picture in iPhoto at the same time as iTunes tries to sync the photo to the ipod/iphone/ipad for the first time.
Note that you won't want to replace your iPad's photos with the ones in iTunes if you've got photos you have synced onto your iPad from a camera memory card or via USB using Apple's iPad Camera Connection Kit. You'd presumably have to get them off the iPad some other way first (email or MobileMe?)
You can connect your iPad to your Mac and NOT sync: Open iTunes, hold down Command and Option when you connect your iPad and wait until the iPad appears in the iTunes sidebar. The iPad will skip the automatic sync. Then launch iPhoto or Image Capture and download the photos to your Mac.
I've not used the Camera Connection Kit - do those photos end up somewhere other than in the Camera Roll album (which isn't touched when you replace photos from the Mac)?
Putting the cache inside the library package is really annoying. You're forced to back it up this way, and that's just a waste.
Just checked on my Mac: this applies also to the Aperture Libray!
So if you're syncing photos from Aperture to your iOS device, you get an iPod Photo Cache folder inside Aperture's library too?
Is this a problem when iPhoto is never used?
My problem is different but might be related. iTunes, or at least the synching process, seems quite capricious regarding which images make it from Aperture to my iPad or iPod Touch. Usually only some of the images in a project or album make it and I haven't discerned the algorithm yet. What experience have others had?