First make sure you backup your data in /Music/iTunes on an external HD or a USB drive
Launch Terminal app /Applications/Utilities/
Kill iTunes app and processes by typing
killall "iTunes Helper"
- Type this command to delete iTunes:
sudo rm -rf /Applications/iTunes.app/
- Type in your password which won't be shown
- Quit iTunes and go to to /Applications, click once on iTunes
- Hold down CMD + I or right click on it and choose “Get Info” from the menu
- Expand “Sharing & Permissions”
- Authenticate your account by clicking on the lock icon in the lower right corner
- Under “Privilege” set “Everyone” -> “Read & Write”
- Close the Get Info window and now drag iTunes to the Trash
- Empty the trash
Now iTunes is completely uninstalled. Download it again from Apple, be sure your devices are running the latest version of iOS (6.0) and try to sync.
If the process above is not working, try to reset your iDevice.
Backup your data first!
Download your iDevice firmware by typing in Google, i.e. iPhone 4 iOS 6 download.
Store it in your Downloads folder or Desktop.
Put your iDevice in DFU mode:
- Plug your iDevice to your Mac \ PC
- Turn it off
- Hold down Sleep button and Home button for about 10 seconds
- Release Sleep button but keep holding down Home button until iTunes recognizes a device in Recovery mode.
- Hold down OPTION (Mac) or SHIFT (Windows) to restore from .ipsw
- Select your previously downloaded firmware and wait for the operation to complete.
I HIGHLY recommend to set the iDevice as a new one and not restoring it from a backup (this will avoid general slowness issues or various incompatiblities). But, if you really need it, restore from backup and try to see if the sync works.
I take no responsibility for anything that may go wrong during the following or mis-following of any processes listed above.