How to Stop iPhone and iPod Auto-Syncing in iTunes

When you plug an iPhone or iPod into a computer that has iTunes installed on it, iTunes automatically opens and tries to sync with the device. Apple designed this as a convenience; it cuts out the step of having to open iTunes manually. But there are a number of good reasons for wanting to stop auto syncing for your iPhone or iPod.

Reasons to Disable Auto Syncing in iTunes

You may prefer not to have iTunes automatically try to sync for reasons such as:

It's not your computer. If you plug your iPhone into your work computer, or a computer belonging to someone other than you, you may want the device to charge, but not try to sync
It's not your primary computer. The computer could belong to you, but if it's not the one you normally sync with, it won't have the correct data on it and won't work properly
You don't have time. Depending on how much data you have to sync, or if you're having problems with syncing some kinds of content (when I've had problems syncing music in the past, sometimes it's taken hours for a basic sync), it can take a long time, which you might not have.

Whatever your reason, the steps you need to follow to stop auto syncing vary slightly based on what version of iTunes you have (though they're roughly the same for all versions).

NOTE: These settings don't apply to syncing over Wi-Fi, only to direct USB connections.

Stopping Auto Sync in iTunes 12 and Newer

If you're running iTunes 12 and up, follow these steps:

Connect your iPhone or iPod to your computer. iTunes should launch automatically
If necessary, click the iPhone or iPod icon in the top left corner, just beneath the playback controls to go to the Summary screen
In the Options box, uncheck the box next to Automatically sync when this iPhone is connected

Click Apply in the bottom right corner of iTunes to save your new setting.

Disabling Auto Sync in iTunes 11 and Earlier

For earlier versions of iTunes, the process is fairly similar, but the steps and text are slightly different. If your version of iTunes doesn't have these exact options, find the ones that are the closest match and try those.

Before you plug the iPhone or iPod into the computer, open iTunes
Open the Preferences window (on a Mac, go to the iTunes menu -> Preferences -> Devices. On a PC, go to Edit -> Settings -> Devices)
In the pop up window, click the Devices tab
Look for the checkbox labeled Prevent iPods, iPhones, and iPads from syncing automatically. Check it
Click OK at the bottom of the window to save your changes and close the window.