Post by Aron / May 18th, 2010

Fixing slow iTunes sync of iPhone, iPod Touch, iPad (the backup issue)


Cheese Cat image by Javier via Flickr

Update October: As you can see from the comments this solution does work for most users with iPad, iPhone and iPod Touch. Please leave a comment, which App causes the slow backup.

Since months I searched for a solution to fix the slow iPhone sync without restoring my iPhone or having to reinstall all my Apps. Finally I found a surprisingly easy solution, covert and buried in an Apple support forum thread. So I decided to write this down here, also to better remember how to fix it the next time… ;)

Note: If you’re wondering, this is still a development blog for Flash. I just thought this might be an important information for the people out there.

What causes the slow backup?

It’s the Apps! Apps on the iPhone might store data to work properly. Some do store a lot, some don’t. For instance a game saves some highscore data (not very much), where a newspaper App or a rss reader might save updated data (can be very much). I believe lots of iPhone users, that experiencing slow backups, have problems with one or many Apps that are leaking in terms of saving tons of tiny files to the iPhone, especially when they have a lot of Apps and when they did backups cross devices (i.e. iPhone 2G to iPhone 3GS).

First try the easy fixes

However, some users got the sync problem fixed with relatively easy solutions. You want to check them first.

- Huge Camera Roll
- Reset Warnings
- Also, I experienced, that iTunes seems to have problems when the hard drive with the music files is not connected to the computer.
- Make sure the latest iTunes version is installed.

Find the evil App

When the solutions above does not work for you, it’s probably an App (or many Apps) causing the backup problem.

First it’s generally a good idea to remove Apps that you don’t need anymore. I know, iPhone users (including me) tend to leave unused Apps on the device. Removing those apps saves you space on the device, speeds up the backup process (even if the app it not evil) and keeps the backup folder within iTunes small. So clean up!

Didn’t work? Ok, let’s go hunting…

1) Find the backup folder on you hard drive

Windows XP:
\Documents and Settings\USERNAME\Application Data\Apple Computer\MobileSync\Backup

Windows Vista / Windows 7:
\Users\USERNAME\AppData\Roaming\Apple Computer\MobileSync\Backup

Mac:
\USERNAME\Library\Application Support\MobileSync\Backup

The folder has a strange long name like 6de624828c9d586e1f088f932798039e57e2af7c. To find the right folder (if you find more than one) open the settings in iTunes, go to devices and find the list “Devices backups”. Match the date of the last backup and the date of the folder.

2) Connect the iPhone and sync

First the backup progress bar in iTunes should move “normally”. After a while the progress bar stops. Probably this is the moment, where iTunes is backing up an App that is causing the endless loop.

3) Find the app

Get into the backup folder. Sort after date, so the newest files are on top. Every file iTunes backups actually consists of two files. The file with the data (.mddata) and an info file for that (.mdinfo), both again with a strange long name. While we cannot look into the actual data (can be an image, a html file, a plist file or whatever), we can have a look into the info file and see at least which App the file belongs to.

Start a text editor and open the .mdinfo file. It’s a binary file, so we see a lot of crap, however you also should see a string like this AppDomain-com.kayak.travel. There you go, the app iTunes is currently trying to backup is the Kayak app (Note: This is just an example, Kayak did NOT cause the slow backup in my case).

Wait some seconds. As you can see in the folder, the .mddata files a relatively small, so iTunes should move on to the next .mddata/.mdinfo file soon. iTunes still tries to backup the same file? Wait some more seconds. Still the same file? Well, we have a hit! The file iTunes tries to backup is corrupt.

In my case however, iTunes continued to backup files. So again, open the newest .mdinfo file. Same app as before? Wait another minute and open the newest .mdinfo file. Still the same app? Well, we have a hit! Although iTunes didn’t stop to backup, it has a hell of a lot to do by copying all files of the app from the device to the backup folder.

Note: Maybe iTunes continues to another app after a while and gets slow again. Then you have more then one “evil” app.

Let the sync run through (if it’s stuck, cancel it).

Do a clean backup

Unplug the device.

We want iTunes to make a clean backup. Copy the backup folder to somewhere else (can take some time). After this is finished, delete the backup in “Settings” -> “Devices” -> “Device Backups”.

Now delete the evil apps from the device.

Connect the device. Start iTunes (if it doesn’t start automatically). Start a sync (if it doesn’t automatically). Since iTunes does not find a backup file, it’ll do complete backup, which may take a while.

After that is finished do another sync, it should be super fast. Yeah!

Happy!

For me the App that caused the problem, was a newspaper app, that seemed to keep all (old) articles on the files system of the iPhone. After removing the app everything went back to normal.

A side effects was that the size of my backup folder went from 1GB to 100MB.

Sources: sbessel in Apple support forum, iphonealley.com – Clean backup

10 Trackbacks

  10. synchronization starts very slowly
    May 1st, 2012 / 15:55

107 Comments

  1. PabloJune 22nd, 2010 / 04:39 / #1189

    Hey Aron,
    Thanks for this information. It was extremely useful as I was going mad with the Iphone back up.
    In may case it was an application from the telegraph uk with information about the world cup that slowed down the backup to more than one hour when normally would take 3 or 4 minutes. I just followed your steps and fixed it up.
    Thanks again
    Pablo

  2. cwoodfieldJune 22nd, 2010 / 06:05 / #1190

    Would the newspaper app in question happen to rhyme with “Blue Fork Rhymes”?

  3. AronJune 22nd, 2010 / 09:24 / #1191

    @Pablo Great! :)
    @cwoodfield Not sure. Please let us know if it was.

  4. JakeJune 22nd, 2010 / 15:56 / #1192

    I looked up this information as I had left my ipod touch to sync for over 3 hours when it usually takes about an hour. This information is really useful.
    I think it may be the Telegraph app too that is causing the problem.

  5. AronJune 22nd, 2010 / 16:26 / #1193

    @Jake Wow, still one hour? Seams that you have a lot of apps on that device.

  6. TipuJune 22nd, 2010 / 23:13 / #1195

    Thanks, this fixed the slow backup problem. News related app was the culprit, deleting the app from the iphone did the trick.

  7. BethJune 25th, 2010 / 22:23 / #1197

    I have a really bad problem. I only have about 29 songs on my iPod touch, and 770 songs. No videos, and not even half a page of apps. My iPod touch was backing up for ten hours the other night , and it didn’t even finish backing up. It’s not even funny, it’s taking overly long. And I have to leave my computer on, which overheats really well.
    Does anyone know anything else which could speed up the process?

  8. BethJune 25th, 2010 / 22:26 / #1198

    I meant 29 photos, not songs :)

  9. bonJune 28th, 2010 / 04:23 / #1201

    Hi,
    I had 18GB of apps (don’t know why they eat so much space) on my 32GB iphone and I have backup for more than 4 days and the progress bar is not around 70%. Should I cancel the backup process ? I know it is still running and when I check the mdinfo file, I think a newspaper apps cause this problem. should I wait for the rest of 30% to complete ? (as I haven’t backup for more than 3months). I afraid the screen will burn because of this long process since it wont goes off during backup.
    Any suggestion ? Thanks a lot

  10. AntonoJune 29th, 2010 / 00:00 / #1202

    Thanks!

    I had tried for months to find a solution to this to no avail!
    Your fix actually worked! And, yes, it was a news reader for me as well…

    Now, this made me realize that all the other “solutions” I found on the internet were useless.

    Worse than that, all the so-called solutions Apple officially offers about this problem are hopelessly irrelevant!

  11. Louis1919July 1st, 2010 / 17:05 / #1210

    Yes!! That trick save my iPod life!
    I used the dual boot to mount my disk in Linux and made some useful research on patterns found in *.mddata files.

    I had 22K files in 1.1 G
    the expression bb.co.uk was found in 5000 of them!
    [ grep bbc.co.uk *.mddata |wc -l ==>5000 ]

    Then I delete all of the BBC news related application and voilà!
    OS4 is now well installed and data well restored.

    NOTE: I opened a ticket with Apple in this subject. I paid for this services no ? they didn’t give me any advise. Pathetic…

    Thanks again guy!

  12. FrankJuly 8th, 2010 / 13:24 / #1221

    Hey Aron thank for you time it’s truly appreciated.
    I found my .mddats & .mdinfo file I tried looking through the info files but I can not find one .mdinfo file with an app domain in it. How can you tell from this file which is the problem app/file?

  13. AronJuly 8th, 2010 / 14:07 / #1222

    Well, it has to be somewhere inside the .mdinfo file. However, the name might not be the name of the app. Sometimes you need some guessing… :|

  14. FrankJuly 8th, 2010 / 14:21 / #1223

    Hey Aron,

    I have randomly cecked and I can’t seem to fine this corrupt file. Can you help me understand this portion of your explaination “Wait some seconds. As you can see in the folder, the .mddata files a relatively small, so iTunes should move on to the next .mddata/.mdinfo file soon. iTunes still tries to backup the same file? Wait some more seconds. Still the same file? Well, we have a hit! The file iTunes tries to backup is corrupt. ” Can I actually see the back up proccess in the file, confused?

    Thank you,
    Frank

  15. AronJuly 8th, 2010 / 14:28 / #1224

    I guess the point you missed is: You need to sort the backup folder (with explorer on win and finder on mac) ascending after date. Then you will see the files flying by during the backup process.

  16. FrankJuly 8th, 2010 / 14:41 / #1225

    ok so during the restore from back up I’ll look for the new folder to appear than go into that folder and watch as the files start appearing and see which one is running slow or in my case which one cause my phone to re-loop the backup process over & over……….?

    thanks,
    Frank

  17. AronJuly 8th, 2010 / 14:52 / #1226

    1) Backup, not restore from backup
    2) It’s not one file that causes the slow backup. It’s loads of files from the same app.

  18. FrankJuly 8th, 2010 / 15:00 / #1227

    Ok well my problem my be different. I upgraded my phone to 0s 4 and now I’m trying to restore from back up……..it seems to you thru the restore fine until it trys to syn once itune reopens…..that when I phone going into the endless loop of syncing than rebooting…….

  19. PaulJuly 10th, 2010 / 14:17 / #1230

    Thanks, this worked a treat, I was able to update to iPhone OS4 after I had removed the bad app. App.sniper. Thanks again.

  20. VivianaJuly 17th, 2010 / 22:36 / #1246

    OH MY GOD thanks sooo much! I feel like screaming! The backup for the new software (before this trick) took me 4 hours to be 2mm thin!! Now, its moving VERY fast!! 1/3 done in 10 minutes!! :D :D :D The only “evil app” for me was GRAAL CLASSIC!!!!! I HATE YOU GRAAL!! and I looove you aron!! THANKS SOOOOO MUUUUCH!!!

  21. JanLJuly 20th, 2010 / 16:22 / #1250

    Hello, this is a very useful post ! Another culprit is LinkedIn that actually saves a file for every profile you ever visited (and maybe even for every contact of every profile)
    ==> just adds a few hours to your backup !

    I guess Apps developers should be way more careful with this file mechanism !

  22. anonJuly 24th, 2010 / 09:23 / #1260

    Thanks a lot! This fixed my iPad backup issues… turned out to be the Weather Channel app. Previously, the backups would run for 7+ hours… now it only takes 10 minutes.

  23. noelJuly 28th, 2010 / 06:54 / #1267

    Aewsome – thank you great help

  24. NicoleAugust 2nd, 2010 / 18:00 / #1275

    This is strange…. My iPod DID in fact finish backing up, and there were no evil apps, but yet it still took ten hours…. There’s over ten THOUSAND files in the backup folder, but yet I deleted a bunch of apps the other day.
    I have about five pages of apps now.
    Any ideas/suggestions/solutions?

  25. Mauro SalaAugust 3rd, 2010 / 13:15 / #1277

    On Windows 7 you can find .mddata

    C:\Users\%user%\AppData\Roaming\Apple Computer\MobileSync\Backup

    :)

  26. AronAugust 3rd, 2010 / 14:27 / #1278

    @Nicole Did you follow the tutorial step-by-step? Wasn’t there a app that slow down the backup process?

    @Maura Thank, I updated the post.

  27. BengtAugust 3rd, 2010 / 15:10 / #1279

    I have the slow sync problem and I have followed you instructions but it does not stop on any particular file but I have like 18 000 files in the backup folder!!! I have maybe 50 apps installed and no music…. Any ideas? I just realized… maybe Spoitfy offline playlists could be the issue?? I will try deleting them.

  28. AronAugust 3rd, 2010 / 15:12 / #1280

    @Bengt Please let us know…

  29. BengtAugust 3rd, 2010 / 20:22 / #1281

    After an excruciating 4h sync I upgraded to 4.01 (had 3 before) but it took like 5min to boot the phone. I got really mad and I started tossing out apps and I started off with the #1 suspect – Spotify, and what do you know… it now syncs in 1min or so. The number of files in the backup folder is down from almost 18 000 to 8 695.

  30. AronAugust 4th, 2010 / 09:05 / #1282

    Thanks for the info. I’m using spotify myself, however with way less offline tracks I guess… :)

  31. NicoleAugust 6th, 2010 / 20:09 / #1286

    @ Aron
    Yes, I did, and there was not a single app that slowed the whole thing.
    It was just a bunch of files all spread out:/

  32. NicoleAugust 6th, 2010 / 23:14 / #1287

    OHMYGOD :O
    So I have over ten thousand files right?
    Well my iPod’s been backing up for about 6 or 7 hours now, AND OVER HALF OF THE GODDANG FILES ARE FROM GRAAL.
    Viviana, I should’ve trusted you.
    I should’ve deleted Graal the second you mentioned it to me…..
    Good lord.
    Is it too late? Should I stop the backup and just restart the thing?
    So my conclusion is, it’s not just ONE file that’s stopping the whole thing up, it’s one APP.

  33. NicoleAugust 6th, 2010 / 23:19 / #1288

    I’ve decided.
    I just stopped the backup, deleted Graal, and am now restarting it…
    Wish me luck:D

  34. GwenAugust 7th, 2010 / 04:10 / #1289

    Amazing, a free app I let my kids download that they never played with turned out to have wasted hours and hours of my time! THANK YOU!

  35. JeffAugust 9th, 2010 / 16:13 / #1293

    Trillion thanks..!!!

    This really help. It resolved my problem which cause my headache for months!!!

    Brilliant !!!! I just removed the evil app… wish me good luck..!!

  36. AliAugust 17th, 2010 / 04:56 / #1297

    All of u fed up from the slow backup. listen the only method i found working.
    it seems difficult in the begining but b patient u will resolve the issue in some time. thanks for publisher.

  37. pauloAugust 17th, 2010 / 13:04 / #1299

    It worked for me very well…. I have to say that i also cut all Pictures out of the Iphone DCIM folder and saved them on my pc. After that with no pictures on the Iphone the Backup was already faster….After deleting also a ” evil app” i am back to 3 minutes backup +sinc.

    Best fix ever

  38. DaveAugust 17th, 2010 / 18:59 / #1300

    Wow. Great info here. Removed all the bad apps and even removed the backup directory before it would backup fast!

    backup directory.
    C:\Users\%user%\AppData\Roaming\Apple Computer\MobileSync\Backup

    Cheers

  39. JimAugust 22nd, 2010 / 12:38 / #1305

    This is very good information. I am finding, however, that the slow backup is caused by photos stored on my ipad. In every mdinfo file, I have a string like Media/PhotoData/Thumbnails/00000/00000/00086.jpg. Before starting the backup, i had several hundred photos on the ipad, but had deleted all but 40. It seems that the thumbnails for all the rest are still there and still slowing the backup. Does anyone have ideas how to delete these thumbnails?

  40. painting servicesAugust 28th, 2010 / 00:21 / #1311

    (Using XP) I went to C:\Users\%user%\AppData\Roaming\Apple Computer\MobileSync\Backup while synching and found 3 backup folders in there all being synced to simultaneously! Quit the synch and deleted all the folders. No wonder the backups were REALLY slow. I’m hoping the next synch will be a lot faster now.

  41. mzbikAugust 30th, 2010 / 23:49 / #1312

    iPad slowness is something else. I have zero apps and I put a single 1Gb movie onto the iPad. On 32 bit windows 7, sync is zippy. On 64 bit windows 7, sync is pokey.

    USB should support gazillions of small files. It’s not an app problem.

    Apple needs to fix this.

  42. nVIDIASeptember 1st, 2010 / 23:24 / #1314

    Thanks Aron

    its really work

  43. EliasSeptember 5th, 2010 / 16:13 / #1322

    The way iTunes backs up any files not directly stored by it (videos, songs, photos) is horrible. What’s the point of getting 64GB ipad and not being able to put even 1 GB of files, risking hours of backup. This has been an issue since April and there’s no reply from Apple yet. It’s not the developers’ fault in any way, it’s just the criminally stupid way that iTunes backs up application files. I had around 5GB of comics in ComicZeal and it kept syncing for 5 hours to get only around 20%… This is unacceptable. There’s no way I’ll stop using the apps I bought my iphone for just because iTunes was coded by monkeys. Even version 10 has the same damn problem. Wake up Apple.

  44. DeanoSeptember 12th, 2010 / 15:44 / #1327

    This is fabulous. A very simple piece of forensics to identify the offending app … now my apps update and backup fast and easy (curse you Inkling!)

  45. FernandoSeptember 19th, 2010 / 13:55 / #1334

    You tip worked very well. I was very unhappy with this backup situation. Yesterday it took more than 4 hours, and now, less than 3 min. Thank you very much for sharing your knowledge with us,

  46. JosSeptember 21st, 2010 / 16:01 / #1336

    Thanks !! Performed the steps and removed several bad apps from my iPad including the linkedin and wired magazine apps.

  47. TimSeptember 22nd, 2010 / 01:06 / #1337

    What a HUGE help. My total sync time was about 12 (painful) minutes. Used your advice, found “Photo Sort HD” was causing the sync to halt for 10 minutes in the process. Removed it and now sync is about 90 seconds! I actually waiting until entire sync was complete, then simply reviewed the results – thanks for saving the most valuable thing I can control my TIME!!

  48. MattSeptember 22nd, 2010 / 15:07 / #1338

    This is awesome. iPod Touch Backup went from apparent infinity (the longest I actually waited was just over 12 hours) to less than 30 seconds (!) after removal of one offending app–from a Kong Kong newspaper called Apple Daily. What is it with newspaper and magazine apps?

    Thank you, Aron. Awesome post that deserves all the Google love it is getting.

  49. ambielSeptember 25th, 2010 / 09:20 / #1346

    I’m trying to follow your method and it seems I got stuck with an app called AppDomain-NBGI0002. Any ideas which app is it? Thanks!

  50. ambielSeptember 25th, 2010 / 09:53 / #1347

    Nevermind. I figured it out. Your method is really great. Thanks a lot!

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