sync session failed to start

AHAH! I had this problem, started after I upgraded to ios6 in my iPhone 4S. COuld not reliably sync or backup to my Windows PC iTunes with either itunes 10.x or 11.x. Same issue with my new iPad3. Drove me crazy for weeks. Finally, as a last gasp attempt, I completely uninstalled SafeEyes from my PC. An viola; everything works now! Sync, backup, both the iPhone 4s and iPad 3. So if you have SafeEyes installed it WILL cause these issues.

yep it worked for me. thanks guys.

Things moved around a bit in the recent update to iTunes, so you need to look under Edit to find the Preferences section.

Select devices.

Delete backup.

Click reset sync button.

Eject phone from iTunes but do not unplug.

Close iTunes.

Reopen iTunes.

Phone will start to sync.

This worked perfect for me. Thank you.

This is ridiculous - these posts have been going for a couple of years now and it is still happening. Apple still claiming they never heard of it and no fix in sight. I upgraded to the latest version of the iTunes two days ago and that’s when I started losing the will to live… First it trashed every music file off my hard disk – I don’t use the cloud and don’t want to – end of… The songs did not “magically” reappear in my folder as some suggest. I had to re-rip all my old CD collection. Next I uninstalled and re- installed iTunes at least 4 times – it kept telling me it could not recognise my iPhone or iPod because this was not 64 bit I Tunes [despite the iTunes download clearly stating it was 64bit]. I finally uninstalled everything Apple and went on a left over file hunt and found – wait for it – drum roll ---over 1000 files plus hundreds of registry entries. In the end I used Revo to uninstall Apple totally. By now I had spent literally 20 hours trying various fixes and ripping music again. I then reinstalled an older version of iTunes – definitely 64bit. It seemed to work, but caused concerns as this was supposedly a vanilla install it still had some of my user preferences set in preferences – so god alone knows where they were hiding.. Now I am at the “cannot sync because cannot start session” messages on both iPod and iPhone… but I think I have a way round it that maybe Apple marketing may find useful. After 24 hours maybe solid work on this useless pile of rubbish I am going into town and buying a windows 8 phone… Simple solution as Apple has become more buggy than a Bolivian Swamp on a hot day.. It’s stared to make Microsoft look stable ……. And at least MS do try and improve their software in their fixes…

Worked for me as well, but only after i restarted iTunes, so make sure you do that!

I have the same issue.

I just got the iPhone 5 (three days ago) and am on iOS 6.1.4 and iTunes 11.0.3.42. I have the iTunes Match and the iCloud options turned off in both iTunes and on iPhone (never turned it on in either place), did the uninstall and reinstall, reset the phone and not only can I not sync music, I cannot even drap-n-drop from my Library to the device. I've even resynched trying the Entire Library vs the Selected Playlists. I've received the error message "unable to sync due to sync not started" but I shut down and reboot iTunes and no dice. When I right-click a song and select Add to Playlist to send it to my iPhone, it never shows up. I've followed every single suggestion I've found and NOTHING works.

Meanwhile, I have not had a single issue with syncing photos - just with the music.

This is unacceptable. This has clearly been an ongoing issue and Apple really needs to fix this.

This worked although I don't have a 'Reset Sync' button, only Delete Backups. My problem started after manually downloading and installing iTunes 11.0.4. This was the 2nd time that iTunes told me I had a new version to install but when I said do it, the App Store came back and said I have NO UPDATES?!? I think the last time it took a few days of playing this game before App Store found it!

Yes, Apple's Mac OS X is going down the same path as Ms's Windows!

I dont know if anyone has answered your question yet, but i have a solution anyways!

Double click home button, close all open apps, do a soft reset, quit itunes if its open. 🙂

No one else has provided any ideas. Thank you for this idea but I tried this three times and it still won't sync my music and I still get the sync error message. Thanks anyway!

Message was edited by: jbuck101

So I broke down and contacted Apple Support. Would you believe that the problem was not only something totally stupid but it is also something that isn't mentioned ANYWHERE in any documentation?

If you've tried all other suggestions and you still can't get your music to sync from iTunes to your iPhone, try this: in your Music list in iTunes, all the songs that you want to sync need to have the little checkmark next to them or there's no way they will sync. You can use CTRL+A to select all then right click and select "Check Selection". Then try syncing again.

I'm baffled as to why this is a non-issue for my 3rd gen ipod but there you have it. I hope this helps someone else.

PS. The error message "unable to sync.." occurs when you try to sync more stuff than you have room for on your iphone and is usually due to photos (though not always).

im having the same problem but ive been trying to resolve this issue for about a month now I have tired everything even disabled my fire walls for a little bit and rebooted everything still nothing someone please help me i need music on my phone ASAP

No music is syncing to my iphone i cant do anything

As I understand it, the error message occurs when you try to sync more "content" than you have space for. Usually this is due to the number of photos but is sometimes caused by other items (apps, music, tv shows, movies, etc).

Have you double-checked to see that the songs in your Music Library all have checkmarks in front of them? If not, you need to add them or you will not be able to sync. You can use Edit -> Select All, then right click the selection and select Check Selection.

Good luck!

Fixed for me by restarting my iPhone 4s (IOS7.0.2). I guess I just had too many apps running on my iPhone. My iTunes is version 11.1.1.11 on a windows 7 64 bit. Hope that helps someone.