iPhone: The Missing Manual, 2nd Edition

Conflicts

If you use only one machine at a time, you'll never have conflicts. You'll never change your dentist appointment to 3:00 p.m. on the iPhone, but change it to 4:00 p.m. on your computer, between syncs. Or you'll never edit a phone number in Contacts simultaneously in two different ways on the two different machines. One machine would always be the "hot potato."

In the real world, though, conflicts occasionally happen. Fortunately, iTunes is pretty smart about handling them. In fact, you can set it up to warn you if more than, say, 5 percent of the address book or calendar is now different from what's on your computer.

In Windows, you set up this alert in iTunes at Edit→Preferences→Syncing. On the Mac, go to your Applications folder. Open the iSync program; choose iSync→Preferences.

The same preference screen also gives you access to the Reset Sync History button, which wipes out the computer's record of your data-sync sessions (but not the data itself). This can be useful if your iPhone just won't sync right and you want to start clean.

If, when encountering the conflict warning, you don't know what could possibly be that different in your contacts file, click Show Details. You're shown a list of all the contacts that will be affected if you go through with the change. Better yet, you get a Before and After button for each one, so you can see the discrepancies up close. That way, you can make an informed decision to Sync or Not To Sync (that is, cancel).

Many conflict problems ...