There are several services (or "processes") running in the background when iTunes is installed on your computer (automatic when you are using Mac OS X, and after you install iTunes on Windows). These include iTunesHelper.exe, AppleMobileDeviceHelper.exe, iPodService.exe, etc. - their name on Mac simply don't include the "
.exe" extension. All these services allow iTunes to monitor background activity, which includes when "i" devices are plugged into a USB port of your computer - be it an iPod, and iPhone, or an iPad. While you can disable these services, doing so will cripple some helpful background functionality - instead, as you'll learn in this tutorial, you can configure a device never to trigger an automatic launch of iTunes, as is the case by default. This setting affects a particular iPod/iPhone/iPad for this particular computer, so you can have different behavior for each device on any PC or Mac.
Start by plugging a Apple device in your computer - an iPod will do, but the principle is the same for other devices:
You can change that setting at any time, and resume iTunes to automatically launch simply by checking that checkbox and applying the change. If your mobile device is configured to auto-launch iTunes and this doesn't happen, it means (most probably) that an advanced user on your computer has disabled one of the background services we mentioned earlier - just resume them and the problem is fixed. In some, very rare, cases, it could mean that your iPod is corrupted and needs to be restored to its factory settings.