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 Already Selling Unlocked iPhone 4s In The US –
Apple said that they would not be selling unlocked iPhone 4s’ till late november but a few memebers of the public have reported that they have been able to buy a unlocked phone. The unlocked phone is reported to come with packing which does not contain a carrier logo or infomation. To activate the unlocked iPhone 4s the user will simply have to plug the phone into itunes and then will recieve a pop up saying you “Your iPhone has been unlocked”. The unlocked iPhone 4s does come with a AT&T Sim card but of course is removable and replacable.
Apple is selling the unlocked iPhone 4s for $649 for 16GB, $749 for 32GB and $849 for 64GB.