When you select the "Synchronize with .Mac" checkbox in the .Mac pane in System Preferences and attempt to sync, you may receive an alert message that says:
.Mac Sync Error
This computer is no longer registered to sync with .Mac - perhaps it was unregistered from another computer. Please re-register this computer using the .Mac System Preferences and try again.
If this happens, you may also notice that when you click "Register This Computer," your computer won't get registered.
This can occur if your computer name or long Mac OS X user name contains an ampersand (&). To resolve this issue, either update to Mac OS X 10.4.1 or later, or change your computer name or long user name so that it doesn't contain an ampersand.
To update Mac OS X, either use the Software Update pane of System Preferences, or find the latest update on the Apple Support Downloads page.
If you choose to change your name, there are a couple of places to check to make sure there's no ampersand in the name:
- Open System Preferences (if it isn't open already).
- Click Sharing.
- In the Computer Name field, change the text so that it no longer contains an ampersand.
- Click Show All at the top of the window to display all preferences.
- Click Accounts.
- Make sure that none of the users of the computer have names containing ampersands. (For example, use "Jack and Jill" instead of "Jack & Jill".)
- Click Show All at the top of the window to display all preferences.
- Click .Mac to display its preference pane and register your computer for syncing.
- Click the Sync tab, then click Sync Now to sync.