100. Synchronize Your Information Using .Mac  BEFORE YOU BEGIN 30 Configure Networking Manually 45 Sign Up for .Mac
 SEE ALSO 51 Keep Your iDisk in Sync
The power of synchronizing your computer's information really becomes apparent if you have a .Mac account and more than one Mac. Using Mac OS X Tiger, you can subscribe each computer to the .Mac server and choose certain classes of data to keep synchronized; Mac OS X then works behind the scenes, gathering your data together from disparate locations such as Address Book, Safari, Mail, and iCal, as well as the saved passwords in your Keychain, and constantly compares it against your contacts, bookmarks, passwords, and calendar events that are stored on the .Mac server. Whenever it finds any discrepancies, it automatically makes the change in whichever system is more out-of-date. 100. Synchronize Your Information Using .Mac 
 TIP Because .Mac synchronization depends on each Mac being set to the correct date and time for it to be able to tell which computer's information is the most up-to-date, it's very important for you to make sure that all your Macs' clocks are accurate. See 26 Enable Automatic Time Synchronization (NTP) for instructions on how to make sure each of your Macs always has the correct time.
If you add a contact or a bookmark on one Mac, the sync process publishes that change to .Mac. On your second Mac, its own sync process notices that there are newer changes on .Mac than on that computer. It downloads and incorporates the changes from .Mac, thereby propagating your most current information from the first Mac to the second. And the best part is that this is all done transparently , in the backgroundyou don't even ever have to know that it's happening. All that matters to you, the user , is that all your most current information is always available on all your Macs. Before Mac OS X can do this service for you, however, you must configure it to do so. This involves registering each of your Macs with the .Mac server, so that each Mac's sync process knows how many other Macs it's negotiating with and how recently each one's information has been synchronized. TIP Even if you only have a single Mac, synchronizing your information with .Mac is a good thing to do, because it protects your valuable data in case it's lost from your own computer. If, for instance, your Mac crashes or you get a new computer, you can immediately restore all your contacts and calendar events by simply subscribing the computer to .Mac and synchronizing the data. To do this, go to the Reset Sync Data button on the Advanced tab of the .Mac Preferences pane and configure it to replace All Sync Info on this computer with information from .Mac.
| 1. | Open the .Mac Preferences
Open the System Preferences application (under the Apple menu). Click the .Mac icon to open the .Mac Preferences pane. Make sure your .Mac member name and password are correctly entered.
| | 2. | Open the Sync Tab NOTE Mac OS X attempts to synchronize with the .Mac server only when you have an active network connection. To set up synchronization or register your Mac, you must be connected to the Internet. Click the Sync tab; this validates your .Mac account settings, registers your computer with .Mac, and shows the .Mac Sync settings screen. To see all the computers registered with your .Mac account, click the Advanced tab. This can be helpful in showing you which computers have been synchronizing successfully and which ones have the most up-to-date information. | | 3. | Select Data to Synchronize The .Mac Sync Preferences window now shows you the status and configuration of your .Mac synchronization. Using the check boxes, choose what kinds of data you want iSync to keep updated. You can select or deselect your Safari bookmarks, the contact cards in Address Book, the saved passwords in your Keychain, the events and To Do items in iCal, and the settings of your accounts in Mail. Select the Synchronize with .Mac check box and choose a time period from the drop-down list to tell Mac OS X to attempt to connect to .Mac at regular intervals, and if successful, to synchronize all your data in the background. With this option selected, you should never have to worry about your personal data being out-of-date again. NOTE Every Hour is a good interval to choose to synchronize your data, especially if you have a permanent Internet connection. If you have an intermittent connection or a low- bandwidth dial-up account, you might choose a longer interval to keep your connection from slowing down every hour as it synchronizes. | | 4. | Perform the First Synchronization
When your synchronization options are configured to your liking, click the Sync Now button. Mac OS X connects to the .Mac server and exchanges your user information. It downloads the data that's in your .Mac account, compares it to what's in your computer's Address Book, iCal, Mail, Keychain, and Safari, and adds any new entries into them.
| | 5. | Resolve Conflicts If Mac OS X finds conflicts similar but not identical Address Book cards or other items that appear on both your computer and .Macit shows you the relevant details of the two items that are causing the problem. Click to select the version you want to keep and then click Finish . Mac OS X will have to sync again to finalize the resolved conflicts. Click Sync Now in the confirmation dialog box to kick off this cleanup-duty sync process. NOTE If you don't resolve the conflicts right away or aren't prompted to resolve them during the sync process, the number of conflicts appears in the Sync Status System Menu; click the <#> Conflicts menu option to resolve the reported conflicts. Quit System Preferences . Your Mac will now synchronize your data automatically every hour, in the background, as long as you have a network connection. | | 6. | Add Sync to the System Menus  Select the Show status in menu bar check box to position the Sync Status System Menu in the menu bar above the upper-right corner of the Desktop. Now you can view at a glance when your computer was last synchronized with .Mac, and also run a manual sync process whenever you choose. |  |
