Earlier this week I had a near-catastrophic issue with Mac OS X Mail on my work computer (a pretty sweet 24-inch 2.8GHz iMac with 4GB of RAM). Every time I launched Mail, the iMac collapsed to a dead crawl. Beyond an occasional slow-motion tremor, all applications seized up and stopped responding. This included the Finder, so I was unable to “Force Quit” Mail. I dedicated (wasted) about two hours trying various troubleshooting schemes, including restarting the computer, booting into safe mode, running Onyx, and following some advice on Macworld.com about rebuilding Mail (links at the end of the article).
Eventually I was able to get Mail to launch and download a few emails before crashing again. My MobileMe email was working fine via the web, as was Gmail; the problem seemed related to my work email account.
I couldn’t figure out what the problem was – after all, I had successfully checked my work email earlier that morning at home. Then it crossed my mind that I had launched Mail at work while a sync with MobileMe was running in the background. Hmmm. Now, I don’t know if that was the actual cause of the problem, or if it was something else. However, circumstantially, it seemed the culprit was a bum sync.
This gave me an idea to resolve the issue. If a bad sync caused the problem, maybe a good sync could fix it. In Mac OS X System Preferences you can find .Mac (and now MobileMe) Sync preferences. I had my Mail accounts and rules set to sync between four Macs. Back at home, I chose to reset all data on MobileMe with data from a computer that I knew had good, healthy data, including all Mail accounts. After I reset the data on MoblieMe, I used that data to reset all data on my work computer. And… it worked! I’m back to successfully syncing all my computers with MobileMe. So far, so good (so far). I was lucky that I had good data at home; I also had a good Time Machine backup at home in the worst case scenario.