Sometimes when you need to sync your iDevice with more than one PC, iTunes on each of them will try to backup your device. You can prevent that (it is however good idea to make backups on at least one of your computers). Option that needs to be changed is not available in GUI, but can be directly changed in iTunes config file. Here is how to change it:
- Shut down iTunes, make sure it is not running.
- Find your iTunesPrefs.xml.You should be able to find this file in C:\Documents and Settings\username\Application Data\Apple Computer\iTunes (on Windows 7: C:\Users\...).The directory "Application Data" is hidden, so please check if you have enabled showing hidden files. It is a good idea to make a copy of the iTunesPrefs.xml before changing anything.
- Open iTunesPrefs.xml in a good text editor (I use Notepad2, but Notepad++ should do it as well. Don't use Windows Notepad, as it will break the file.
- Find the phrase "User Preferences" and then paste the block below after the first <dict> tag and before the <key> tag.
- Save the config file. After you start iTunes again, Backups will be disabled. To change the setting back, just find the "DeviceBackupsDisabled" block we have added in steps 1-4 and remove all four lines.