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Galaxy S7 Fingerprint Sensor Unreliable


I simply wish to flag the fact that the Galaxy S7 fingerprint sensor appears to be very poor in that it often doesn't work despite my having recorded all four of the available images using the same finger.


When it has worked once it seems more likely to work again for a few hours, before consistently failing to do so thereafter.


I have tried wiping the key, and I suspect also that there is a particular right way of placing one's finger thereon, with the device being acutely sensitive for example to the degree of pressure applied.


It ought however to be able to use this technology reliably and with a minimum of fuss. All in all very disappointing.



Superuser I
Superuser I
Hi! got to say never had much issue with mine :( I would say try starting again and re doing the registration (How to do here and when you re do the finger print sensing try to move the finger print at different heights whilst keeping the scanner in the same position. And see if that helps I had to re do mine the 1st time as I got to excited and kept my finger in the rough same place and didn't scan the whole finger print which made mine not read right at 1st. Give it a go see what happens. **you should not need to press to hard on the sensor**

Thanks for the advice. I'll do what you suggest although I have re-set my fingerprints on numerous occasions, and each time it works fine for perhaps two or three days before the proportion of failures becomes unacceptable. I wonder whether my fingerprints are the problem. Are they prone to change perhaps?


Apart from the issue itself, the documentation provided on how to set this up and use it is very poor and needs a redical overhaul. One should not have to post on a forum for a detailed explanation!


Superuser I
Superuser I

Yeah would be great if the documentation was better guess its like flat pack furniture lol as for you finger prints it should not change to much only time I have had real issues was when I had, had my hands in water for a long time lets keep our fingers crossed it works for you (no pun intended).


Hey @Rational!

How did you get on with @Bades1978 advice? 

If you're still having issues with this, can you go to Apps > Settings > Device Maintenance > Storage > Clean Now. 

I was just 'scanning' the messages and came across this (Pun intended). 


No improvement I'm afraid. The link to the instructions simply repeated what I already knew because it was documented elsewhere, and there was no more detailed information on any subtlety as to how one should perform a fingerprint scan. At the moment I'm re-scanning my fingerprint each day, and all four stored fingerprints are from the same finger, but if anything, the problem is getting worse.


I could try your suggestion of Apps > Settings > Device Maintenance > Storage > Clean Now, however before I do so, what exactly will this do? What if anything will be cleaned apart from the the fingerprints, and why would this be necessary if everything worked as it ought to? I'm wary of bricking my phone.


Aside from the obvious problems that I'm having, the design of the UI seems odd. Why would the fingerprint sensor be co-located with one of the on-off buttons if there is only a minimal association between the operations that the respectively enable? The col-location makes understanding how to operate power on and fingerprint scan obscure, and indeed for a while I actually believed, in my view quite reasonably, that the mere act of depressing the button and then releasing it would suffice for a previously scanned fingerprint to be recognised.


By the way, e-mails notifying me of a post are visible in my phone, but not in Outlook 2003, even when I download pictures. This is a nuisance, and it would be useful to know of a fix, although it's not my primary concern.


Hi again @Rational

Thanks for getting back!

My suggestion will free up storage space by deleting unnecessary data such as cached, residual, and advertisement files. This clears the cache partition for each application without the need for you to go into the app individually to clear the cache partition. Sometimes files can hold cached data which needs a bit of a clear out to get functioning back to full capability. 

This won't brick your phone so there's no need to worry about that. 

I've personally found that adding the same finger print (or thumb in my case) more than once can usually make it more sensitive and recognise your print. Try the first one with your finger flat and move this ever so slightly. Then add another one but use the same finger/ thumb. Start this slightly on its side and move it central when advised to do so. 

Do you find that you're unable to use the fingerprint scanner when you've locked your phone and then try to get back in straight away? 

Go into Settings > Lock screen & security > Secure lock settings > Lock automatically > Change it to Immediately.


Thanks JordanH.


As you suggested I've done a Clean Now, just on storage, and then deleted all fingerprints, wiped the phone's glass and then added two prints from the same (index) finger. At the moment the phone is unlocking as it should however this is not unusual following re-adding of fingerprints. The proof of the pudding will be whether it continues to do so in a day or so's time.


I don't know whether trying to get back into the phone immediately after having locked it was a factor: I suspect not but I have set Lock automatically to Immediate anyway.


I couldn't really follow your advice on moving the finger while the print is being scanned. The phone issues instructions on what to do and how to do it, and it's always a struggle to get to 100% and hence complete. If I'm not being told to wipe the key, I'm being informed that I must make sure that the finger covers the whole of the home key, and the latter in particular seems to preclude angling the finger rather than holding it flat, or starting with the finger tip. My fingers aren't particularly small either: I'm male and though not heavily built my hands are certainly not like those of most women.


Thanks again anyway. I'll post back with an update in a couple of days.


By the way, do you have any thoughts on my problem reading e-mails notifying that someone has posted?


That's great, @Rational!

Keep us updated on how you get on with this! 

As for your email issue, we'd recommend creating a new thread about this and we'll get back to you there. :smileyhappy:


Hi JordanH,


I'm afraid that there's still no improvement in the operation of the fingerprint sensor. If anything it's performing even worse than usual, and although my hands and hence my index finger are dry through gardening I've re-recorded my fingerprint several times and never have fewer than four such recordings stored. My fingerprint is sometimes recognised, though latterly only occasionally, so I don't think there's an underlying hardware problem. Perhaps there is something odd about my prints, but I am disappointed that this feature of what is a premium device doesn't simply work reliably.


As I mentioned previously the documentation is poor. There is no guidance on, for example, what the optimal amount of pressure to use is, and how sensitive recognition is to variations therein. Also I frequently get a message saying 'Wipe the Home key and Try Again', but does this always mean that the home key is greasy or simply that recognition has failed? I seem to spend a lot of time rubbing to no avail.  When recording one is advised to move the finger up and down, and to change its angle relative to the device. Indeed one has to do this in order for the recording to reach the 100% required for it to be stored. However when attempting to use the finger to unlock the phone one cannot apparently place it arbitrarily: orientation seems to be everything.


I'm only seeking to use fingerprints to unlock the phone, but this is just as well because as things stand I couldn't rely on it for the making of payments etc.


One good thing to come out of this is however that I've noticed Smart Lock. This might help me not get annoyed when using the phone at home.


Sorry that I can't be more positive.


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