Hi, not sure if there is already a thread on this but I have tried a search. I have just upgraded my iTunes to 11.4 and now neither my iPad Air or iphone 5 (both on iOS 7.1.2) will sync. They both appear in iTunes and I can access the tabs and check/uncheck music ect but the sync button is greyed out. I have tried the back up button and making a change then hitting 'apply' but both start to sync then stop after about a 2 seconds with no error message. The usage bar at the bottom just shows everything on my devices in the yello 'other' category. I have downloaded the ios8 update for both devices but neither will run as I just get an error saying that iTunes cannot back up the device after the software has been extracted and it then stops. Any help would be appreciated, I can't understand why I can no longer sync either device. Many thanks.