Anytime an iOS device is connected to a computer it will sync and backup the device, and though the syncing process can be annoying sometimes, the backup process should be considered crucial so that you always have a way to restore your iPhone, iPad, or iPod should anything go wrong.
With that said, there are a few limited situations where some users may want to disable the iTunes & iOS backup process completely, which is different than stopping iTunes from automatically syncing because it continues to allow for device syncing but minus the backing up aspect.
We’ll show you how to turn off backups, but we want to warn everyone this is not a good idea unless you know what you’re doing and why you’re doing it, leaving this option best for select jailbreakers or just for demonstration purposes.
Disable iTunes Backups for iOS Devices
- Quit out of iTunes and launch the Terminal, then enter the following defaults write command:
defaults write com.apple.iTunes DeviceBackupsDisabled -bool YES
- Relaunch iTunes, connecting iOS devices will sync but without a backup copying over
With backups disabled nothing will be added to the local directory or iCloud, and anything already there can be deleted through iTunes or manually. Remember, disabling this feature removes the ability to restore an iOS device should you need to, which for 99.9% of people is a bad thing.
Re-Enable iTunes & iOS Backups
- Quit iTunes again and launch Terminal, entering the following defaults command:
defaults delete com.apple.iTunes DeviceBackupsDisabled
- Relaunch iTunes and connect an iOS device to confirm backups are working again
The instructions above are intended for Mac OS X, but Windows users can disable the device backups by launching iTunes with a flag attached to it, this can be executed from the Run menu or by right-clicking iTunes:
"%ProgramFiles%\iTunes\iTunes.exe" /setPrefInt DeviceBackupsDisabled 1
To reenable backups with windows, change the 1 to a 0 and run iTunes exe again.
//************************************************************************************ Prevent file be backup
https://developer.apple.com/library/ios/#qa/qa1719/_index.html