The iPhone "..." could not be synced because the sync session failed to start

Solved "sync session failed to finish" by performing a restore to iPhone. Choose from my backup and all is well and all my data, music, apps, etc are back just fine.

Thanks everyone!

iPhone 4 cdma on iOS5 using iTunes 10.5(141)

Hope this helps!

I'm on an iPhone 4s with iTunes 10.5. I've tried all the recomended steps and I am still mgetting this same issue. It also happened with my previous phone the 3Gs in iTunes 10.5 after upgrading to iOS 5.

Not impressed that the issue has carried over to even a new phone.

I just tried the "Restore from backup" suggestion and nothing. Got all the data there, but no sync. Also deselecting various options for the sync (like calendar, mail and so forth) seem to have no effect. The reboot of both mac and iPad has no effect either on the issue.

A 'funny' issue is that I can play all the media on the iPad through iTunes. I can even from iTunes delete it.. but this carries only in iTunes, the Ipad is totally unaffected by it. Even after disconnect and reconnect it.

(iPad2 iOS 5.0 (9a334) iTunes 10.5 (141))

marben100 wrote:

The nature of the problem seems to be the iTunes software timing out if you try to add too many photos at once: it seems to then "stick" at the message "Waiting for changes to be applied" and eventually it just returns the error message "...could not be synced because the sync session failed to finish". Adding folders a few at a time seems to solve it.

Not working for me. After once again restoring to factory settings I synced just one folder from my Aperture library. Went fine. Added another folder. Fine. After hitting the eighth folder the sync stalled. Restored to factory settings as nothing else helped I managed to get to the fourth folder this time. Inconsistent results. And just a week ago my iPad2 with 4.x OS was just fine and my iPhone 3GS with 4.3.5 is still syncing the pics just fine. So definetely not a library issue (?).

Apple, wake up and fix this! I have of course given direct feedback on Apple/feedback.

So... if I am not technically minded... and when iTunes told me there was an update available... I just updated.. I didn't check what I needed to do first... and now I am getting an error message saying the iphone ..... could not be synced because the sync session failed (or something like that..) How do I update my beta (whatever that is) ... or how do I fix this problem... I don't want to restore if I don't have to.... HELP HELP HELP!

I found a 'solution' of sorts, still doesn't explain WHY it didn't work, but for right now the sync works.

I downloaded and installed iTunes again.. on top of my excisting version. Then It started to sync again.

I am having this problem now, was able to sync yesterday morning, but this morning I am getting the error

The iPhone “xyz iPhone” could not be synced because the sync session failed to start.

It happens in step 1 of 7 "waiting for sync to start"

I downloaded iTunes 5, then it told me to backup my iPhone 4 before I did the new iOS 5....but alas, it won't allow me to backup. 4 hours on the phone with Apple Tech last night and I am still in this issue this morning.

Could have sworn I left windows for better than this.

I tried almost everything everyone mentioned here with no luck. I finally decided to restore my iPhone. It may be redundant, but make sure you do a back up before you restore, and then sync your phone after the restore is complete. This worked for me and now everything that is supposed to be there is!

I just re downloaded and repaired the iTunes install (win64 bit) and my phone is now working perfectly again.

After installing and uninstalling iTunes several times the sync'ing still did not work. So I...

• Uninstalled every Apple-related software (Updater, iTunes, QuickTime) from my computer.
• Saved all pictures, videos, etc., from my Ipod.
• Reinstalled iTunes
• When given the option in iTunes, setup the Ipod as "new"

... and it worked!

I suggest using this method as the last resort.

I have the problem as while and while it doesn't "fix" it i just, with the iphone staying plugged in, close itunes, wait a sec and reopen it and it seems to work fine just doing that. I'm sure they'll fix this in a future update so if this fixes it for now then no big deal.

this worked for me:

Windows 7 Professional, Service Pack 1

iTunes 10.5.0.142

iOS 5.0

The problem started at some point after upgrading both iTunes and iOS but initial syncs appeared to work. Fixed now after some nervy moments during my first restore and backup of the iphone... wasnt entirely sure what would be kept, but everything except my phones 4 digit lockcode seems to be intact.

Just made one very simple move without having to restore iPhone or reinstall iTunes.. 🙂

1st step:http://support.apple.com/kb/TS1538 *Read 'in my case' in here first before following this link*
Follow that link to restart (or if necessary) reinstall your Apple mobile device support.

In my case, Leave iPhone connected all the way. I first exit iTunes. Then i stopped the Apple Mobile device support (by following a part on that link above in step 1) which Effectively made my iPhone undetectable on itunes but discoverable by windows as a 'camera device'. Then while device is still connected, i started the Apple mobile dev support again. Now i open itunes and there my iPhone re-appears.

2nd step: After your iphone re-appears on iTunes, press Sync and all is well... 😉

P.S, Mine is iPhone 4 running on iOS 5, iTunes 10.5, Windows 7..