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
Apple Seed Mac OS X 10.7.3 To Developers –
Yesterday we seen Apple release iOS 5.1 beta 3 to developers. Now they have just released Mac OS X 10.7.3. Acording to a few developers Apple is asking developers to focus their testing on the following areas: Address Book, iCal, Mail, Spotlight, and Safari. This beta weighs in at 1.26 GB.