It's been a tough week for Apple. First, there were the activation hassles during the iPhone 3G launch day. Next up were the numerous complaints about poor 3G network signal strength and batteries that lose their charge too quickly. (Expect these to be resolved via future updates to the iPhone software.)
Amidst all of this, it's hard to choose exactly which one or two issues to highlight here. Ultimately, I decided to focus on two lesser known fixes for iPhone problems--fixes that, nonetheless, can resolve a wide range of sync symptoms.
Fix iPhone sync problems by reinstalling iTunes
After switching over to an iPhone 3G, I discovered that syncing my iPhone's Contacts list had gone astray. In particular, syncing was now inexplicably unidirectional--only from the Mac to the iPhone. Any changes I made on the iPhone itself were eradicated after a sync. Among other things, this meant that ringtones I had assigned to contacts (which cannot be linked except on the iPhone itself) would not survive a sync. Very annoying.
I went through a laundry list of potential fixes, none of which had any effect. What finally succeeded (and a tip of the hat to Apple tech support for guidance here) was to completely remove iTunes from my Mac and reinstall it.
To do so on your Mac, drag iTunes to the Trash, restart the Mac and then empty the Trash. Next, go to the iTunes download page to download and install the latest version of the software. After I did this, I was pleasantly surprised to find that my sync problem was gone.
A related not-well-known but often helpful fix is to launch iSync, select Preferences from the iSync menu, and click the Reset Sync History button (as noted in this support document). I might have tried this before I set about to reinstall iTunes--but the button was grayed out and unselectable on my Mac. Interestingly, reinstalling iTunes fixed this glitch as well. While a sync reset should leave all your data intact, I recommend playing it safe and backing up your Address Book and iCal data before proceeding.
Fix MobileMe-to-iPhone sync problems by deleting the MobileMe account
After setting up MobileMe, I noticed that none of my calendar changes on the MobileMe Web site were being pushed to my iPhone. I tried numerous fixes, as suggested in this Apple article. However, I had to go all the way down to the tenth and final suggestion before finding the one that worked: Deleting and re-adding my MobileMe account on the iPhone (via Settings -> Mail, Contacts and Calendars). Especially if you had previously set up a .Mac account on your iPhone that was converted to MobileMe, I recommend starting with this step rather than saving it for last. It costs very little in time and hassle--and is a cure-all for a variety of MobileMe-to-iPhone symptoms.
This story, "Bugs & Fixes: Fixing IPhone 2.0 Sync Problems" was originally published by Macworld.