How to Fix Sync Session Failed to Start Effortlessly

If you are an iPhone user, then you must have come across a ‘sync session that failed to start’ error in your phone.

The error will be persistent on the phone and will not go away that easily. The error has different variations to tit.

Sometimes you will get a clean error saying the sync session failed to start, and other times you will get hit with ‘iTunes could not sync calendars to the iPhone because a sync session could not be started.’

One of the most annoying things about this error is that it doesn’t give any more details about it.

If it had, it would give the user some clue on how to take proper measures to fix the problem on the phone. Many iPhone users have reported on many forums about seeing this problem on their phones.

They even tried to troubleshoot on the PC and iTunes to try to fix the problem. Sometimes this problem would stay longer and won’t take any fix. The only option you will leave is an ok button on the dialogue box.

Luckily there are ways you can try to fix the sync session failed to start error on your phone without taking any drastic measures. Here you will find all the methods you can try to fix the problem more manually and automatically.

All the methods will have various sets of instructions, each crucial to another. So please read it carefully so you can stop the error sync session failed to start from popping up on your system.

If a method doesn’t seem to work out for you, you can move to the next to get the proper fix.

Way 1: Fix Sync Session Failed to Start by Update

sync session failed to start error can show up on the phone if the phone has an outdated program version of iTunes and other software. Make sure to update this software to see if that helps you get rid of the problem.

Here is a detailed guide to fixing the problem.

  • Connect your desktop computer to a network, and after that, launch iTunes.
  • After launching iTunes, then get to ‘Help,’ then from here, go to the ‘Check for update.’
  • Here follow the instructions to update your drivers.
Update iTunes

This will solve the problem; if it doesn’t, move on to the next method.

PS: Click here to figure out how to fix iTunes has an invalid signature during the installation.

Way 2: Fix Sync Session Failed to Start by Delete

Don’t worry; you don’t have to delete your backup data. Sync session failure to start can also be caused by your old iTunes library. Deleting the old iTunes backups will solve the problem on your iPhone.

Follow up below to solve the problem.

  • Goto iTunes > here, make your way to the preferences option.
  • Choose Edit > Preferences option (For windows).
  • After that, click on the devices.
  • Here will see the list of backups. Select the one you wish to delete. To know more about the backup, you can hover over the cursor on the backup.
  • After you find the right backup to delete, click on ‘Delete Backup’ and then hit ‘Confirm.’
  • That’s it!
Delete backups on iTunes

If this one didn’t do the trick, then switch to the next one for the fix.

Way 3: Fix Sync Session Failed to Start by TunesCare

Here is another software you can use to fix the sync session that failed to start a problem on your iPhone using Tenorshare TunesCare.

This app also has many features that can erase any problem on your phone easily and effectively. Just like the previous software, if you are facing any error on your phone regarding iTunes and other features of the phone.

If you are facing any problem, you can use Tenorshare TunesCare to remove the error off your phone in an instant completely.

Get Tenorshare TunesCare

Follow up below guide to figure out how to remove the error on your phone and make your phone faster.

  • First, you have to download TunesCare and launch it on your PC, although the app does come with many requirements for installation and running. But all modern computers will have enough for a smoother experience.
  • After installation, connect your iOS device to the computer with a USB cable. Tenorshare TunesCare is well equipped with all sorts of functions that will detect the phone and the model name that it carries within it.
  • You don’t have to add all the information about the phone that manual way. This saves plenty of time.
  • When launching it, you can see two options on your screen. One is to Fix iTunes Sync Problems and fix all iTunes Issues.
  • The problem here is that the sync session failed to start, so choose the Fix iTunes Sync Problems to start the repair process.
Tenorshare TunesCare
  • Once the repair process begins, wait patiently until it gets done.
  • After the process, you will see your functions acting normally as it supposed to be or as it once was.
Fix sync session failed to start via Tenorshare TunesCare

That’s it; if you followed all the methods above, you would have a functioning iPhone with Functional iTune options. You no longer have to face the sync session failed to start error on your phone.

If you face any other errors regarding iTunes, you will have software in your hand that will be capable of fixing any problem that is attached to iTunes.


All the methods above will provide you with the best solution to fix your sync session that failed to start a problem on your computer.

As some of the methods have tighter instructions, but if you follow them one by one without missing anything, then you will have all the knowledge to fix the problem in a matter of time, especially for Tenorshare TunesCare. As you can tell, the problem here is persistent.

Sync session failed to start‘ can pop up any time on your computer without giving you any rationale explaining how to solve the problem.

You can try out the methods above to solve the problem if you have a problem with one trying to work with the next one.



Ten years of experience in information and computer technology. Passionate about electronic devices, smartphones, computers, and modern technology.