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 Fingerprint Scanner Details Leaked In Patent
More information has been leaked regarding the new iPhone 5S’s home button revealing an increased chance that it will have a built in fingerprint scanner. The recently found patents seem to explain how Apple will tackle problems of using the main navigation button on the device to allow it to be used to scan the users finger print, possibly, to make a secure purchase within a app. While at the same time providing the useful feature we all know it to do.
The patent suggests that the metal ring around the home button on the iPhone 5S will be capacitive meaning it detects change in electrical charge from your finger. This will trigger a scan when the user holds there finger over the button.
It seems Apple has big plans for the small button which has been rumoured to be axed in previous years. The patent seems to suggest the finger print scanner will not be the only sensor crammed in, since it is likely a NFC sensor plus optical input/output sensors will be hidden there too.