From my experience, MobileMe has an inherent problem with sync data “residue.”
Most of my technical issues with the service’s calendar, contact, and bookmarks synchronization features have resulted from Apple’s cloud service not adequately cleaning up after itself. In my case, this resulted in massive event duplication in my web calendar and on my iPhone, and MobileMe would randomly sync data from months prior. In short, it was a real mess.
During a recent tech support chat with a MobileMe representative at Apple, I learned of an undocumented way to completely nuke all sync data from their servers. And it’s easy as pie.
Now this isn’t some super-secret hack of the service; it’s more of a Homer Simpson d’oh! moment. You know, sometimes you get so used to doing things in just one way and you forget to try alternatives. This is one of those cases.
Normally, to remove the computer you’re currently using from MobileMe, you’d click the “Sign Out…” button under the Account tab of the MobileMe pane in System Preferences, right here:
But this doesn’t really do much of anything. It just logs out your Mac, but leaves its mess of sync data behind.
And according to MobileMe’s support documentation, to fix a sync problem, you should simply reset your sync services folder (Mac OS X 10.5: Resetting the SyncServices folder). This works most of the time, but it only affects data on your local Mac. To truly reset your sync status, you need to purge your data from there server. But there’s no documented way to do this.
So here’s how.
First, make sure you’re working on the Mac that has the most current and up-to-date data on it.
Then make sure all your iCal and Address Book data is backed up. In iCal choose “Back up iCal…” from the File menu and save your back up file somewhere you’ll remember.
In Address Book, choose “Address Book Archive” from the Export sub-menu under the File menu (don’t ask me why both applications don’t provide the same menu structure for this identical command: yet another annoying quirk in the Mac OS). Save your Address Book archive somewhere you’ll remember. You probably won’t have to use these files, but you never know.
Click on the Sync tab of the MobileMe System Preferences pane (pictured above). Then click on “Advanced…” A sheet will drop down that displays all of the computers that are currently registered to your MobileMe account, something like this:
Now click on each computer listed, one after another, and click the “Unregister” button. Leave the computer you’re currently using (identified as “This Computer”) until last.
Now here’s the good part.
After you unregister the computer you’re currently using, a new sheet will drop down asking you what unused sync data you want to delete from the MobileMe servers.
If you’ve been having problems with MobileMe sync, there’s probably all sorts of garbage that’s collected here over time (the first time I did this, it was a total mess), and I’d say just select it all and click the “Delete” button. That will completely remove every trace of sync data from the MobileMe servers. From my experience that sync detritus creates huge problems and removing it can be very effective.
After you finish that, you’ll be back at the Sync tab in the MobileMe Control Panel of System Preferences.
Activate the check box besides “Synchronize with MobileMe:” and leave the drop down menu as “Manually.” Select the items you want to sync from the list below that. This will essentially re-register your current Mac with MobileMe (you’ll have to do this on your other computers, too).
Then click on the “Advanced…” button again and you’ll be back at the list of registered computers.
Click the “Reset Sync Data…” button and make sure you adjust the settings like so:
Then click the “Replace” button. This might seem redundant after having already manually deleted everything from the MobileMe server, but my understanding is that this action sends a “signal” to your other computers to fully re-download all the fresh data from MobileMe (otherwise, they might sync some bad data back up).
After that, sync as normal.
I haven’t been able to find this information anywhere else online, so I hope that by posting it at least one other person will discover it and find it useful. I know that this manual sync-data delete process saved me weeks of headaches alone.
Let me know if it helps, or if you have any problems!