Edit: After half day, my wife’s Mac started having the same problem. I have then applied the solution that I found in the Apple
A Quick Guide on Synching Connected Devices and Mac Running on Mac OS X 10.4
The advantage with Mac OS X 10.4 is how easily you can sync your contacts, mail data, calendars and other information seamlessly between devices, be it Palm based or Mobile devices . All you need to use is iSync version 2.0 to sync these devices with your Mac.
To further ease the process of synching various devices, you can add a Sync Status menu to your menu bar. To do this, launch either .Mac Sync preferences or iSync preferences and move to ‘View sync status in the menu bar’.
Once you get the icon in the menu bar, all you need to do click to sync all the connected devices and Mac is the ‘Sync Now’ option from the Sync Status menu.
iPod Sync Tips
Mac OS X 10.4 can sync contacts and calendars to an iPod. Once it is connected, choose ‘Sync Now’ from the Sync status menu without opening the iSync program.
To sync a phone one has to launch the iSync application and ensure that the phone is already synced. Once launched, you can use the Synch now button from the sync status bar.
Palm OS device tip
If you use a Palm OS based device, you first need to sync it in iSync and then when you want to sync it, connect it and Mac will prompt you to click on HotSync button on the device or its cable or cradle.
However there can be a chance when you want to sync on the connected devices at the same time. For this first open iSync version 2.0 and move to Sync Now option. This lies in the Sync status menu. You will be prompted to click on HotSync on PalmOS cradle to sync the device. Others will be synced as well. Just in case you have to resolve any sync issue during the process, sync the devices again to ensure that there is no data loss.
Many a times during the sync process users confuse Sync Now menu choice with the iSync sync device button. So here is the breakdown of how different the two options are:
• The Sync Device button is used when you want to sync data in devices that have been earlier configured in iSync. This excludes the Palm OS devices as they are synced by a different Hot Sync option.
• ‘Sync Now’ tool or function is used to sync data to an iPod without iSync or with other connected devices if it is open. This also excludes Palm OS devices.
‘Sync Now’ works best for iPod as it doesn’t require you to launch the iSync application for syncing process. However note that it doesn’t work without the iSync application in case of other connected devices. To avoid launching iSync application for these cases, you can add iSync to your Login items, which can be done by following these steps: System Preferences>>Click Account>>>Click Login Item tabs. This ways you won’t have to launch iSync, it will be opened automatically when you login.