Unlock code is required after a restart, rather than just a fingerprint!

[cooldudetouch]

I don't know if anyone has actually realized, but this is a security feature designed to prevent someone who finds your phone (like if you've lost it) from unlocking it. When fingerprint scanners came out there was a huge controversy that anyone could use tape and putty, etc. and lift your fingerprint off the screen, make it into a mould and use it to unlock your phone. This sounds complicated but it was actually a simple process. That is why Samsung decided to prevent fingerprint unlocking upon a restart or not using your device for 24 hours.