MobileMe Sync: About registering and unregistering computers

Register a computer for syncing

If you are using a Mac, simply choose System Preferences from the Apple menu, click MobileMe (or .Mac in Mac OS X 10.4.11), then click the Sync tab (sign in if needed).

If you are using a PC, open the Control Panel, click the MobileMe Preferences, and choose the Sync tab (sign in if needed). When you check (enable) "Synchronize with MobileMe", if your computer is not already registered, it will automatically be registered.

Or, you can manually register your computer:

Mac OS X 10.4.11

1. Open System Preferences
2. Click .Mac
3. Click Advanced
4. Click Register

Mac OS X 10.5 or later

1. Open System Preferences
2. Click MobileMe
3. Click Sync
4. Click Advanced
5. Click "Register this Computer" 

Windows XP or Vista

1. Open Control Panel
2. Click MobileMe Preferences
3. Click Sync
4. Click Advanced
5. Click "Register this Computer"

Unregister a computer from syncing

If you no longer want a computer to sync with MobileMe, you can unregister the computer from syncing. You can unregister any computer that is registered for syncing from any other computer with Mac OS X 10.4.11, Mac OS X 10.5 or later, Windows XP, or Windows Vista, as long as you know your member name and password.

Unregistering a computer from syncing does not delete any data.

To unregister a computer from syncing:

Mac OS X 10.4

1. Open System Preferences
2. Click .Mac
3. Click Advanced
4. Select the Computer you wish to unregister
5. Click Unregister

Mac OS X 10.5

1. Open System Preferences
2. Click MobileMe
3. Click Sync
4. Click Advanced
5. Select the Computer you wish to unregister
6. Click Unregister

Note: In Mac OS X 10.5  or later, if you unregister all computers you may be prompted to delete unwanted sync data. If you are no longer syncing with MobileMe, you can delete the unused sync data from the MobileMe servers. 

Windows XP or Vista

1. Open Control Panel
2. Click MobileMe Preferences
3. Click Sync
4. Click Advanced
5. Select the Computer you wish to unregister
6. Click Unregister

Troubleshooting

If you are unable to synchronize your data successfully with MobileMe, it can be helpful to completely reset sync data on MobileMe and on all of the computers with which you are syncing. To perform the following actions, you will need to have a computer using Mac OS X 10.5. If you do not have a computer with 10.5, you should review the general troubleshooting article for Mac OS X or Windows instead.

NOTE: It's important to back up any data that you wish to keep. Failure to back up your data properly or follow these instructions may result in data loss. Proceed with caution and at your own risk. For more information about backing up, please see How to back up MobileMe data. After backing up your data, verify that the data is properly backed up.

Next, on a Mac that has Mac OS X v10.5 or later, unregister the other computers using the steps outlined in the "Unregister a computer" section above. When the last computer has been unregistered, you will be prompted with "Would you like to delete unused sync info from MobileMe?" Select the boxes next to each of the data types listed and click Delete. 

After unregistering the other computers, sync your data from the computer that has the most up-to-date information. To register the computer for syncing, refer to the Register a computer section above. When you are asked, "What would you like to do for this first sync?", select "Merge" and click Sync. You may have to do this for each data type that you are syncing. 

After you have performed the initial sync, you should try syncing again. If you do not receive any alerts, add additional computers to the MobileMe sync list by following the same register steps from above. When you are asked, "What would you like to do for this first sync?" select "Replace data on this computer" and click Sync. You may have to do this for each data type that you are syncing. This will replace the data on the computer with the data that has been synced to MobileMe. 

You should add the computers one at a time, confirming each time that syncing is working correctly. To confirm that syncing is working, make a change in one of the data types you are syncing, then perform a sync from the first computer. When that syncing is finished, perform a sync on the second. If syncing is successful, add a third computer, and so on. 

If the issue persists after you follow these instructions, please contact MobileMe Support for further assistance.