So I have to setDuplicationCheck() at the point in the loop where I want to check for duplication? As far as I'm aware there is no function which actually carries out the check? There is only a function to "enable" the feature (the set one) and also a function to verify the feature is on: getDuplicationCheck().

I'll even add the serial monitor when I comment out the fingerprint.search function, the code works as intended registering a new fingerprint: 

Here's what's output on the serial monitor: