The latest update of Apple's software, iOS 7.1, is supposed to bring iOS device users a lot of new features like CarPlay, improved finger print scanner on iPhone 5S and a few bug fixes. However, the update is not all smooth. Many iPhone 5S users complain about the iPhone 5S Touch ID issue after updating to iOS 7.1.
This issue includes a complete failure of the Touch ID, the mysterious disappearance of saved fingerprints and difficulty producing a match among others. Here are 3 possible methods for you to fix the iPhone 5S Touch ID issue.
It seems that iOS 7.1 would have turned off the iPhone Unlock option for some users. For this reason, the first thing you should do is check whether the iPhone Unlock is enabled. This can be found under the Touch ID & Password section of the Settings app.
The next thing that you can do is to remove the saved fingerprints from the Settings app and add them on your iOS devices（It can work for the high version iOS 10/9/8/7) again. You can follow the steps below:
If the issue persists, try restoring your iPhone 5S from a previous backup.
Have other issues after updating to iOS 7.1?
For problem like contacts are gone, you can check How to Recover iPhone Contacts.
For problem like iPhone battery drain, maybe you could get some insights from the post How to Fix Battery Life Issue with iOS 7.