iPhone: Prevent Automatic Sync
Posted on Nov 26, 2007 under Hardware Tips |How to disable or prevent your iPhone from automatically syncing when you connect it to your computer.
1. Open iTunes.
2. Click iTunes > Preferences (on a Mac) or Edit > Preferences (on a PC)
3. Deselect Disable automatic syncing for all iPhones.
Now your iPhone will not automatically sync when you connect it to your computer.
Source: iPhone Users Guide

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