Over the holidays, I encountered an unresolved problem where iTunes 7.5 doesn’t automatically launch and sync with an iPhone when the phone device is attached to a Mac running Leopard (OS X 10.5). The launch failure occurs even though auto-sync is enabled in the iTunes preference window (see below).
So far, the only way my customer has been able to sync his iPhone is to first start up iTunes manually. As part of the troubleshooting process, my client deleted the iTunes preference list files that appeared in /~Home/Library/Preferences/ and its sub-folder /ByHost. Doing so, however, has not resolved the issue.