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

Are you running mac or Pc?

I'm running a mac... I just got an update for itunes that fixed my problems... finally.

I'm running a PC. I just updated iTunes as well. I have literally tried every single fix out there.

I'm sorry to here that you are still having trouble.

PC's are a little touchy sometimes, although they are vastly better then they have been.

My suggestion is to wait it out.... and not waist your time with goofy fixes that just get you more upset.

I still trust that Apple is out there and they here us... They will come out an update very soon... 2 weeks or so maybe sooner.

You're best off not to chase your tail on this one...

Of course you could go to Geek squad and let them at it, sometimes its good to have someone else fight it out for you.

Good luck.

You are correct @terryp33. I run a Mac and cannot find anything like the Apple Mobile Device Support. Like other users here, I've tried EVERYTHING out there. I've done 3 or 4 different types of resets, numerous times over, I've deleted itunes twice and reloaded. I managed to recover photos, using the little inexpensive app Mobile Sync Browser, and that app shows that all my texts and data are in the backup, but I just can't get it to restore to my replacement iphone 4 after I broke my old one.

I have years of journaling, years of recipes, business info, inc 34,000 sms's - much of them business.

Annoying. I think I spent 3+ full days & evenings staight trying to fix. I hope Apple don't take too long to fix this, or I'll have to overwrite too much new data. 😐

Hi Jac,

Great news... for us mac types... Not saying this is going to work for you... I'm using a 3Gs iphone not the 4G that you have.

Yesterday I got itunes update 10.5.1 my 3gs phone got an update last week 5.0.1 I'm running my mac book with 10.6.8 do you have these updates?

Hey there i really int understand the solution you have given regarding this beta 1 and syncing with beta 2 .

I jus want you to guide me how can i exactly get rid of this problem.

I am Having a iPhone 4 16Gb white running iOS 5.0.1

and version of iTunes is 10.5.1.42

And having another iphone 4 Black 32GB running 4.3.3 [Jailbroken] [Syncing Smoothly n Properly aving problem only with my other phone [white 16gb iOS5.0.1]

please kindly tell me what do i have to do

Contact : sagar98@gmail.com

Thank you, it fixed my problem.

thank you for your advice. I started to panic, read your directions and worked for me! 🙂

I believe the issue is related to the backup option (iCloud vs computer). If you were playing around with the iCloud setting and were not sure which to pick after upgrading to iOS 5.0+, then set it to iCloud backup and complete the sync. Then if you want to return to the old way of syncing with a computer then select that option AFTER you do the iCloud backup. Something was coded wrong there or Apple is trying to force people to use the iCloud.

Also, I recommend:

1. Emptying your Recycle Bin or Trash. For some reason iTunes puts some old files in there doing the upgrade process. I noticed that someone mentioned this in the first couple posts on this thread.

2. Do a cold reboot of the iPhone before you sync.

For some reason you have to do the Wifi sync to the iCloud first before you can revert back to the old computer sync method. I did not have to reinstall, repair or restore anything.

Hi,

I ran into this issue of, "sync session failed to start" this morning. I am using a 15" Mac Book Pro, running 10.6.8, iTunes, version 10.5.1 (42) and a Verizon 4G iPhone (5.0.1). I was able to fix this issue with the following steps:

1. Empty the trash

2. Disconnect the iPhone

3. Quit iTunes

4. Relaunch iTunes

5. Plug iPhone into iTunes via its USB cable

My phone synced without any problems. Hope this helps.

P.S. I do not use iCloud for back-up. I have not changed any settings for this feature in awhile.

Thanks - this worked for me on iPhone4, iPad2 and iPod touch, all on OS 5.0.1 and running iTunes 10.5.1.42.

I have a PC and a ATT 4Gs. I just did these steps and it worked. Thank you all!!!

If you're running a PC with Outlook on it, then the following may assist:

1. Open Outlook, head to the Addins menu (Tools / options / addins or File / Options / Addins depending on your version)

2. If the itunes Outlook plugin is inactive, change it to active / enabled.

3. Restart Outlook, restart itunes

I felt this was a counter intuitive fix because I do not sync my iphone with Outlook - I'm using an exchange server, but it worked. My impression is that this is poor software design - it's relying upon a component operating that shouldn't strictly speaking be used. Fail.

Other things that might assist in the more general case:

- Itunes, edit, preferences, devices, and reset sync history

I'm running win7 x64 pro / Itunes 10.5.1.42 / iphone 4s ios 5.01

I continue not to be able to resolve this issue on OSX and have tried "Everything" (see below). It is interesting that the same macbook air can no longer sync a 4s and a 4 but can still sync an iPad. I just filed a bug with apple as below:

Summary:

After working fine for some time, I stopped being able to sync my 4S with iTunes on my Macbook Air. It sits at step 1 of 7 for 5 minutes, and then reports:

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

Interestingly, my wife's iPhone 4 will also no longer sync with the same computer. Both used to work fine. However my ipad 1, also on 5.01 sync's fine. I can come up with nothing to the critical question "What changed". Not that nothing did, I just don't know what did that may be relevant.

Things tried:

Restarting iTunes

Restarting iphone.

Sync over Wifi.

Sync over USB (multiple cables)

Disable iTunes Match.

Delete iCloud account.

Resetting All settings on iphone.

Removing iTunes COMPLETELY (all library (both)) and misc settings plus hiding Backup folder.

Reinstall iTunes 10.5.1.

Upgrade iphone to 5.1 beta.

All to no avail. iTunes always fails to start the sync and eventually errors out as above.

Steps to Reproduce:

Attempt to sync iphone via wireless or USB.

Expected Results:

Should have begun sync.

Actual Results:

It sits at step 1 of 7 for 5 minutes, and then reports:

"The iPhone "Jeff Greenhut's iPhone" could not be synced because the sync session failed to start."

greenhut:

Try the following. It's a repeat of what we did above.

Since you're using multiple devices, upgrade ALL devices to the latest OS. Avoid any betas and use the latest stable software (iOS 5.0.1).

After you install the software upgrade, do a cold reboot on all devices.

Then empty the trash can (or Recycle Bin) on everything. iTunes puts some bad files in there which are causing problems. This is a key step. If you have temp files too remove them also.

Since you implied iCloud in your message, I'm assuming that you were messing around with the iCloud settings like I was. You need to do a complete iCloud sync on all devices first. Let it complete. Check the option to sync over Wifi too in iTunes. If the iTunes struggles, go into Settings | iCloud | Storage & Backup and try syncing from there instead.

Once the iCloud Wifi completes successfully on all devices, then try changing the option back to USB and resync again with USB.

There should be no need to uninstall or reinstall anything. Try playing around with the Trash and the iCloud sync.

My setup: iphone4 + WinXP