Symptom
You are no longer automatically notified of available software updates.
Note: This affects any version 10.1 to 10.1.5 when upgraded to 10.2 or 10.2.1. This may also happen if the Software Update preference is deleted. The issue is resolved in Mac OS X 10.2.2 or later.
Solution
To turn automatic notification back on, follow these steps:
1. Choose System Preferences from the Apple Menu.
2. Choose Software Update from the View menu.
3. Select the checkbox for "Automatically check for updates when you have a network connection".
4. If you wish to check for a Software Update immediately, click Check Now.