Just updated iTunes to latest version. iPone 5 OS is 6.1.4. Connected phone to computer via USB. Decided to Sync Calendar - ALWAYS with Outlook. Have set Backups to 'This Computer' - NOT iCloud, so assume sync is always with This Computer and is via the USB, although have ticked 'sync with this iPhone over Wi-Fi' in the Options section. Result: I now have duplicate calendar entries on the iPhone. I've searched for other experiences but find all are related to iCloud usage. So, I am now both confused and, frankly, not best pleased. Help/education from the Forum, with a touch of pity for my ignorance, will be much appreciated. Cheers.