touch id quits working after a few days

[frequent reader]

I have a new i-phone 6S and my touch id is does not consistently work. I have entered various fingerprints and each time the latest print works for a short time and then quits; a previous print quits completely. None of my prints will work. I contacted apple support and a senior rep guided me to connect my phone to my computer to erase the software and reload it. After that, it began to work consistently for about a week. And now again the issue arises. I entered a new print and it will sometimes read that print. Now it will not read any of them. Has anyone else run into this issue? Everyone I know who uses an i-phone has not had my issue. I think it must now be a faulty phone (hardware) and not the software. Help! Any ideas?

 

[iThingsGurl]

You are correct in guessing that you have a faulty Touch ID hardware. I'd suggest you to take it to an Apple Store. They may likely replace your phone with a new one.

Although, the difficult part is you'll have to convince them how it's an issue; you don't want them to reload the software and you register your fingers and then it works for a week or so and then it stops working, again - and the loop goes on. On the plus side, every conversation you have with Apple Support is documented. Hence they will know you had an issue earlier, what steps you were advised in order to rectify it, and that those steps didn't work.

All the best and do let us know how the visit turns out for you.

 

[frequent reader]

You are correct in guessing that you have a faulty Touch ID hardware. I'd suggest you to take it to an Apple Store. They may likely replace your phone with a new one.

Although, the difficult part is you'll have to convince them how it's an issue; you don't want them to reload the software and you register your fingers and then it works for a week or so and then it stops working, again - and the loop goes on. On the plus side, every conversation you have with Apple Support is documented. Hence they will know you had an issue earlier, what steps you were advised in order to rectify it, and that those steps didn't work.

All the best and do let us know how the visit turns out for you.

[doublepost=1460752041][/doublepost]iThingsGurl:
Thanks for your reply. Here's the latest... I reviewed the many similar issues others have experienced with touch ID on the Apple Community site and found an idea that I thought was worth the try. The suggestion was to go into settings-touch ID & passcode: iPhone unlock, apple pay and then undo those. Then restart and go back and re-enter fingerprints and also replace settings (iPhone unlock, apple pay). I did this and, of course, it works. And the encouraging thing is it now will recognize all fingerprints I have entered and it works every time. So I'll give it a week (the usual loop time for it working) and if it quits working, I'll contact Apple again. I agree... convincing the Apple Store folk that this is an issue and then having it work for a week again is probably a continuation of the loop. And is it software or hardware then??? But I also agree, every contact is a communication to Apple that this is not working for me (and I'm sure others). If anyone else has ideas or input.... I'm ready to listen!

 

[dazz87]

Having the same issue on my mom new iPhone 6. It will work great the first day or two and then will stop working all together. Went back and erase it and then add a new fingerprint and it will work for couple of days. I believe this is a hardware issue.

Planning on heading to the Apple Store to get a replacement.

 

[chscag]

Having the same issue on my mom new iPhone 6. It will work great the first day or two and then will stop working all together. Went back and erase it and then add a new fingerprint and it will work for couple of days. I believe this is a hardware issue.

Planning on heading to the Apple Store to get a replacement.

I don't know what causes that to happen. I know of many folks who have the same complaint as your Mom (including me) and it appears that swapping out the phone in most cases doesn't help. I believe it's either a firmware or hardware flaw with the iPhone 6 models (not the 6s). I just got tired of fighting it and use my passcode instead.

 

[frequent reader]

[doublepost=1460752041][/doublepost]iThingsGurl:
Thanks for your reply. Here's the latest... I reviewed the many similar issues others have experienced with touch ID on the Apple Community site and found an idea that I thought was worth the try. The suggestion was to go into settings-touch ID & passcode: iPhone unlock, apple pay and then undo those. Then restart and go back and re-enter fingerprints and also replace settings (iPhone unlock, apple pay). I did this and, of course, it works. And the encouraging thing is it now will recognize all fingerprints I have entered and it works every time. So I'll give it a week (the usual loop time for it working) and if it quits working, I'll contact Apple again. I agree... convincing the Apple Store folk that this is an issue and then having it work for a week again is probably a continuation of the loop. And is it software or hardware then??? But I also agree, every contact is a communication to Apple that this is not working for me (and I'm sure others). If anyone else has ideas or input.... I'm ready to listen!

[doublepost=1462365905][/doublepost]Just an update...The idea found on the Apple Community site to fix my issue with the finger ID did not work more than a week. But it was the longest amount of time it ever has worked after putting in a new print. Now it will not read any prints I've ever done and I'm giving up. I have been in touch with Apple support and they agree that I could work with an Apple Store to set a Genius Bar appointment. I live a distance from the nearest Apple Store and, not wanting to send in my phone and be without it, I"m going to bring it to a store. Unfortunately, I can't arrange an appointment for more than 7 days in advance and that has been irritating. Just want to know I have an appointment since my travel time depends on knowing. To add to my fingerprint issue, the phone has done other odd things that seem to prove it's a hardware issue. Some calls have locked so that I cannot hang up. Very weird! I've also had the phone heat up and a warning came on that the phone was heating. I took a vacation for about a month right after I bought the phone but the issues started immediately. I notified Apple right away but didn't follow-up on the software changeout until we got back and this has been dragging on now for some time. Will they exchange this phone or will I just have to go through "repairs." I have come to believe I have a lemon. What do you think?

 

[iThingsGurl]

[doublepost=1462365905][/doublepost]Just an update...The idea found on the Apple Community site to fix my issue with the finger ID did not work more than a week. But it was the longest amount of time it ever has worked after putting in a new print. Now it will not read any prints I've ever done and I'm giving up. I have been in touch with Apple support and they agree that I could work with an Apple Store to set a Genius Bar appointment. I live a distance from the nearest Apple Store and, not wanting to send in my phone and be without it, I"m going to bring it to a store. Unfortunately, I can't arrange an appointment for more than 7 days in advance and that has been irritating. Just want to know I have an appointment since my travel time depends on knowing. To add to my fingerprint issue, the phone has done other odd things that seem to prove it's a hardware issue. Some calls have locked so that I cannot hang up. Very weird! I've also had the phone heat up and a warning came on that the phone was heating. I took a vacation for about a month right after I bought the phone but the issues started immediately. I notified Apple right away but didn't follow-up on the software changeout until we got back and this has been dragging on now for some time. Will they exchange this phone or will I just have to go through "repairs." I have come to believe I have a lemon. What do you think?

In most cases, iPhones with more than one issues at a time are usually exchanged. You indeed have a bad device. Albeit, you may need to demonstrate those issues to the Genius.

 

[frequent reader]

In most cases, iPhones with more than one issues at a time are usually exchanged. You indeed have a bad device. Albeit, you may need to demonstrate those issues to the Genius.

IThingsGurl:
Thanks for your supportive comments! I've had Macs since the 90's and been loyal to Mac. But this has become so frustrating. I can demonstrate the Touch ID issue to the Genius Bar techs... but how do you demonstrate other issues that happen sporadically? I'll give it the old college try though in a few days when I go to the Mac Store and let you all know.
[doublepost=1462374158][/doublepost]

I don't know what causes that to happen. I know of many folks who have the same complaint as your Mom (including me) and it appears that swapping out the phone in most cases doesn't help. I believe it's either a firmware or hardware flaw with the iPhone 6 models (not the 6s). I just got tired of fighting it and use my passcode instead.

My issue is with a 6 S, not a 6. Pass codes on that phone are 6 digit and more of pain to enter each time for ordinary phone use. I've heard from others that the issue can be sporadic but works most of the time. For me it never works after a bit. And other strange working issues point to some hardware problems. But... I would sure like to hear from 6S users if the Touch ID is an problem beyond my phone. If so... Mac needs to get it on the radar for a fix. I'll be taking my phone to the Mac Store.

 

[daniel1948]

I have had a similar problem with my iPhone SE: I enter three fingerprints, so I can use any of those three fingers. All work fine for a while, and then one or another goes wonky and requires several tries, and then quits working entirely, then another and another.

I delete the one that quit working and enter it again, and it works for a while, and then it all starts again.

The same happens on my iPad Pro, but since the Pro lives at home, I just quit using fingerprint ID on it. I'll take the SE in to the Apple Store next time it's convenient, but I think if the problem was hardware, it would just quit working, rather than slowly forgetting each separate fingerprint one at a time.

 

[frequent reader]

I have had a similar problem with my iPhone SE: I enter three fingerprints, so I can use any of those three fingers. All work fine for a while, and then one or another goes wonky and requires several tries, and then quits working entirely, then another and another.

I delete the one that quit working and enter it again, and it works for a while, and then it all starts again.

The same happens on my iPad Pro, but since the Pro lives at home, I just quit using fingerprint ID on it. I'll take the SE in to the Apple Store next time it's convenient, but I think if the problem was hardware, it would just quit working, rather than slowly forgetting each separate fingerprint one at a time.

Hey Daniel1948: I appreciate the feedback as the SE should operate with some of the same insides as the 6S. While not being any kind of an expert, I would think that hardware as well as software is involved with the touch ID. The sensor for sure. If it were only software, my issue with that specific thing would have been cured when I had the software re-loaded, with the help of a Senior Mac consultant. Worked very well for a while and then started down the path of not working, ebbing into only one or two days of working after reloading fingerprints. I have some other issues too that make me feel that it's hardware. But for both of us, good we're going to the Apple Store and good we're putting this on their radar

 

[daniel1948]

Actually, I wondered if the problem is my fingers. The Skeptics Guide to the Universe podcast has covered the fact that fingerprints are not the absolute end-all of identification that popular culture makes them out to be. Maybe after washing dishes my fingers are wrinkled and that alters the prints beyond what the sensors can identify, or maybe I get a scratch or scrape... I don't know. Maybe the software has a hard time with minor distortions. Since I don't really understand how it works I don't feel I can speculate too much about the causes of a malfunction. I don't even understand how the sensor works. Is there a camera under a transparent cover over the button? Is it some sort of capacitive thing like the touch screen itself? (Okay, I just read on Wikipedia that it's a capacitative reader, but I still have no idea how it works.)

 

[frequent reader]

Actually, I wondered if the problem is my fingers. The Skeptics Guide to the Universe podcast has covered the fact that fingerprints are not the absolute end-all of identification that popular culture makes them out to be. Maybe after washing dishes my fingers are wrinkled and that alters the prints beyond what the sensors can identify, or maybe I get a scratch or scrape... I don't know. Maybe the software has a hard time with minor distortions. Since I don't really understand how it works I don't feel I can speculate too much about the causes of a malfunction. I don't even understand how the sensor works. Is there a camera under a transparent cover over the button? Is it some sort of capacitive thing like the touch screen itself? (Okay, I just read on Wikipedia that it's a capacitative reader, but I still have no idea how it works.)

That makes two of us who don't understand how it works. A little bit of Knowledge is dangerous.. but I've asked those questions about differing aspects of finger conditions and the Mac consultants tell me it would still at least work at some point. And I also wondered about the screen cover I bought with my new phone and they tell me it should not make a difference. We'll see what the Genius Bar folks tell me. What in the world is a capacitative reader? Yikes!

 

[iThingsGurl]

Thanks for your supportive comments! I've had Macs since the 90's and been loyal to Mac. But this has become so frustrating. I can demonstrate the Touch ID issue to the Genius Bar techs... but how do you demonstrate other issues that happen sporadically? I'll give it the old college try though in a few days when I go to the Mac Store and let you all know.

Thank you. By the time your appointment day is up, you can try shortlist various uses which exacerbate heating up of your device - like playing videos for a few minutes. In either case, I think a faulty Touch ID is enough for them to determine that you have a bad device (bad Apple? ). They usually prefer swapping your device with a new one rather than repairing the Touch ID. Lets just hope everything goes smoothly for you, especially since you don't have an Apple Store nearby.

I would sure like to hear from 6S users if the Touch ID is an problem beyond my phone. If so... Mac needs to get it on the radar for a fix.

There have been no known widespread issues with iPhone 6s' Touch ID. In fact, a lot of people have experienced its Touch ID to be exponentially better than previous iPhones. Having said that, isolated issues - like your's - do get reported occasionally.
[doublepost=1462390341][/doublepost]

Actually, I wondered if the problem is my fingers. The Skeptics Guide to the Universe podcast has covered the fact that fingerprints are not the absolute end-all of identification that popular culture makes them out to be. Maybe after washing dishes my fingers are wrinkled and that alters the prints beyond what the sensors can identify, or maybe I get a scratch or scrape... I don't know.

I just faced this problem today! My iPhone 6 refused to recognize my fingerprint after I applied sunscreen.

I don't even understand how the sensor works. Is there a camera under a transparent cover over the button? Is it some sort of capacitive thing like the touch screen itself?

That makes two of us who don't understand how it works.

The surface of our home button is a synthetic sapphire crystal. Below it there's a capacitive sensor whose job is to merely record the surface of whichever object touches it. It then captures this point-of-contact, like a camera takes a photo. Of course, unlike a camera, since this is capacitive, this image is not captured by light but derived by electric current. According to Apple, its image resolution can be as much as 500 ppi (Apple Watch's display has a resolution of about 326 ppi). This image is then passed on to the processor which does the rest of the job.

If you have already registered your fingerprint, the processor will compare this image to the pre-existing image. If a match is found, your device will be unlocked. For consumers' privacy, Apple does not allow any other app to access this fingerprint data.

 

[daniel1948]

I am going to make a point of cleaning the button and washing my hands the next time it becomes reluctant to recognize my finger. If that does not fix it, I'll schedule a visit. Also, as suggested above, I'll note whether anything had been running at the time. In any case, whenever it's happened, deleting the fingerprint and re-entering it has always got it working again, so it's not a catastrophic failure.

Apple says that fingerprint ID makes the phones more secure, even though it really makes them less secure by providing an alternate way in, because the fingerprint is so convenient that people who would not otherwise bother to lock their phone will now do so. That's definitely me. I would not bother to lock my phone. I have no critical data on it. But I want to use ApplePay (at the tiny handful of places that take it) and ApplePay turns off and deletes your cards if the phone is not passcode-locked. And using a passcode every time I turn the phone off is a pain in the keister, so I use fingerprint ID.

 

[C DM]

I am going to make a point of cleaning the button and washing my hands the next time it becomes reluctant to recognize my finger. If that does not fix it, I'll schedule a visit. Also, as suggested above, I'll note whether anything had been running at the time. In any case, whenever it's happened, deleting the fingerprint and re-entering it has always got it working again, so it's not a catastrophic failure.

Apple says that fingerprint ID makes the phones more secure, even though it really makes them less secure by providing an alternate way in, because the fingerprint is so convenient that people who would not otherwise bother to lock their phone will now do so. That's definitely me. I would not bother to lock my phone. I have no critical data on it. But I want to use ApplePay (at the tiny handful of places that take it) and ApplePay turns off and deletes your cards if the phone is not passcode-locked. And using a passcode every time I turn the phone off is a pain in the keister, so I use fingerprint ID.

Seems like that improves things by having more people securing their devices and by allowing them to use a more complex passcode if they wish since they wouldn't need to use it all the time (and thus keep it simpler for convenience).

 

[daniel1948]

Seems like that improves things by having more people securing their devices and by allowing them to use a more complex passcode if they wish since they wouldn't need to use it all the time (and thus keep it simpler for convenience).

I still cannot use as complex a passcode as I'd like, since I still have to remember it. The ideal passcode would be 20 or 30 totally random characters. And if TouchID really worked reliably, that's what we could all use. But since it so often fails, we have to be able to enter the passcode, and that means one we can remember. So the only real advantage of TouchID is that we can use a slightly longer passcode that is slightly more of a nuisance to enter, and people who would not use a passcode at all and just leave their phone unlocked, can lock it.

 

[C DM]

I still cannot use as complex a passcode as I'd like, since I still have to remember it. The ideal passcode would be 20 or 30 totally random characters. And if TouchID really worked reliably, that's what we could all use. But since it so often fails, we have to be able to enter the passcode, and that means one we can remember. So the only real advantage of TouchID is that we can use a slightly longer passcode that is slightly more of a nuisance to enter, and people who would not use a passcode at all and just leave their phone unlocked, can lock it.

Even a slightly longer passcode, let alone an alphanumeric passcode compared to a more typical 4 digit one that people would often make simple, is exponentially more complex and secure from security point of view. Not sure about TouchID often failing either as that isn't the case for most. So, again, it seems to overall make things more secure, at the every least to some degree, not less.

 

[daniel1948]

The thing is, TouchID makes the phone more secure for people who would otherwise leave it unlocked or use a very weak passcode* and who have switched to a more secure passcode now that they can use the fingerprint instead, but makes the phone less secure for someone who was using a very secure passcode and now for convenience uses the fingerprint. And it makes little to no difference in the security if the person uses TouchID but keeps a weak passcode.

* I actually saw someone type 0000 into their phone as a passcode.

Most secure is a complex alpha-numeric passcode that is not based on any personal information or simple pattern, and with TouchID disabled.

Less secure is the above passcode with TouchID enabled for convenience.

Much less secure is a weak passcode, regardless of whether TouchID is enabled.

Least secure is an open phone with no protection at all.

TouchID improves security only in those cases where it motivates people, by its convenience, to implement a more secure passcode than they were otherwise using. (I am in this category. )

 

[C DM]

The thing is, TouchID makes the phone more secure for people who would otherwise leave it unlocked or use a very weak passcode* and who have switched to a more secure passcode now that they can use the fingerprint instead, but makes the phone less secure for someone who was using a very secure passcode and now for convenience uses the fingerprint. And it makes little to no difference in the security if the person uses TouchID but keeps a weak passcode.

* I actually saw someone type 0000 into their phone as a passcode.

Most secure is a complex alpha-numeric passcode that is not based on any personal information or simple pattern, and with TouchID disabled.

Less secure is the above passcode with TouchID enabled for convenience.

Much less secure is a weak passcode, regardless of whether TouchID is enabled.

Least secure is an open phone with no protection at all.

TouchID improves security only in those cases where it motivates people, by its convenience, to implement a more secure passcode than they were otherwise using. (I am in this category. )

Don't really see how it makes it less secure for someone that had a complex passcode and uses TouchID with it. Overall it seems like it makes things more secure, or at the very least not any less secure.

 

[daniel1948]

Don't really see how it makes it less secure for someone that had a complex passcode and uses TouchID with it. Overall it seems like it makes things more secure, or at the very least not any less secure.

It adds one more way to get in. TouchID is hard to hack, but it can be done. TouchID increases security only if it gets you to use a more secure passcode than you had before.

TouchID would leave the system as secure as it was without it only if it were 100% unhackable, which is not the case. With a highly secure passcode, the only way in is to hack the phone system itself or coerce the user into divulging the passcode. Add TouchID and now someone can get in by hacking the phone system, coercing you into divulging your passcode OR forcibly pressing your finger on the button, OR obtaining your fingerprint and spoofing the system.

Adding more ways in will always reduce security, other things being equal.

The benefit to TouchID is that a complex passcode is a nuisance to key in every time you turn on the phone, so TouchID will likely get people to make their passcode more secure. And it's good enough for most of us. Nobody wants the information on my phone badly enough to go to the bother. Thus TouchID is nice. But if you really have critical information the loss of which would be a disaster, you'd better use a very secure passcode and disable TouchID.

 

[frequent reader]

RE: my touch ID issue and my update.... I followed up with an Apple Store Genius Bar appt. on Friday. They insisted it just needed a "fix." To review... this is a brand new phone with this issue developing immediately upon purchase and reported thusly to Apple. I had the software reinstalled and gone through all the hoops the Sr. Apple reps have put me through. I live 150 miles away from an Apple store and finally was able to fit it in my schedule to travel there to follow through with a Genius Bar appointment. They decided on a "fix" and installed a different display assembly. Here we are 2 days later and the same issue reappears again, as I knew it would. First one print will not be recognized–ever–and the same for the other prints. I need to keep re-entering fingerprints. This is a hardware issue requiring a full exchange for another phone, a new one, of course since my phone was new! I will be returning to the Apple Store again later in May. I feel like they are putting me through these hoops when we all know this is a hardware issue that can only be resolved by replacing the phone. I've been an Apple customer for years and years and have been loyal. This is the first time I feel compromised by Apple. Furthermore, they took off my new screen shield during the Genius Bar appointment and it ended up lost on their floor and later found cracked. Of course, I can get that new shield replaced but will have to pay for postage, making this whole thing more costly, besides the irritation factor. This whole brand new phone "fix" is costing me time, money and a lot more gray hair. Is there such a thing as a lemon clause for i-phones? Any advice. Guess I'll just have to get angry and make demands. But... will I get anywhere? Maybe I should have purchased the Samsung phone???

 

[daniel1948]

FWIW, my touch ID has worked without problems since I last re-set my fingerprints. <Touch wood!> This morning it demanded my passcode, but I think it does that every couple of days as a security measure. (?)

Frequent reader: If you reported the problem within the 14-day return period, and they were unable to fix it, I think you should be able to demand that they take the phone back and refund your money in full. Then it would be up to you whether you want to buy another (or take a brand-new one in exchange) or switch brands. I don't know what the law says, but you could certainly make a strong argument that since they could not fix it they owe it to you to extend the return period. It might be as simple as talking to a different service rep. Good luck. No product is 100% perfect, and it sounds like you got a lemon. As a long-time Apple customer, it's in their interest to make things right with you, and I think there's a good chance they will, if you can get hold of a sympathetic rep.

 

[frequent reader]

FWIW, my touch ID has worked without problems since I last re-set my fingerprints. <Touch wood!> This morning it demanded my passcode, but I think it does that every couple of days as a security measure. (?)

Frequent reader: If you reported the problem within the 14-day return period, and they were unable to fix it, I think you should be able to demand that they take the phone back and refund your money in full. Then it would be up to you whether you want to buy another (or take a brand-new one in exchange) or switch brands. I don't know what the law says, but you could certainly make a strong argument that since they could not fix it they owe it to you to extend the return period. It might be as simple as talking to a different service rep. Good luck. No product is 100% perfect, and it sounds like you got a lemon. As a long-time Apple customer, it's in their interest to make things right with you, and I think there's a good chance they will, if you can get hold of a sympathetic rep.

[doublepost=1463413455][/doublepost]Daniel1948: Glad your issue is resolved. Nice! I'll keep working with Apple with my issues but am disappointed with them. I've been loyal to Macs for years. All my technology has been (and is) with Apple products over many, many years. So far the responses from them with this issue are professional but "canned." Guess they follow their protocol but have not been very personal or understanding. I've been easy to deal with, not tough either. It is in their best interest to work with me satisfactorily but I get the feeling that business is so good that they are losing sight of how important each customer is. I'm a realist & know that things are not perfect but expect more personal customer services....

 

[MiniGeek]

The touch ID on my first iPhone 6 was wonky right from the start as well. It would work for a while, and then stop. And for a while, I mean less than a day. I used different fingers and ended up with the maximum number of fingerprints entered and I would quickly get to the point where none of them would work. Then I would delete them all and start over again. I figured the issue was my fingerprints. I wash my hands frequently and my skin gets dry, so I always thought that was the problem. My spouse, also with the iPhone 6, has never had an issue with his.
Other issues developed with the phone, which ultimately ended up being hardware and the phone was replaced 4 months after I bought it. Hardware issues involved the wifi antenna, which died a slow death until it quit entirely, and the bluetooth, which died totally along with the wifi. At the time, I didn't connect the touch ID to all of that, but after having replacement phone #2 and having a properly functional touch ID for the first time, I do think my touch ID was faulty from the start. As it was with phone #2...although I was still blaming dry skin.
Yesterday morning, when I woke up, my phone asked for the passcode. I thought it had restarted during the night. This is what my first defective iPhone was doing when the hardware issues started, so I was alarmed. But now that I think about it, I don't recall seeing that message on the screen, only that the passcode was needed to enable touch ID. My spouse says his does that every couple of days or so as well, so I guess it's not a big deal. My other two iPhones never did, probably because I had to reset the touch ID so many times that it never had the chance.
It looks to me like the whole touch ID technology still needs some fine tuning.

 

[frequent reader]

The touch ID on my first iPhone 6 was wonky right from the start as well. It would work for a while, and then stop. And for a while, I mean less than a day. I used different fingers and ended up with the maximum number of fingerprints entered and I would quickly get to the point where none of them would work. Then I would delete them all and start over again. I figured the issue was my fingerprints. I wash my hands frequently and my skin gets dry, so I always thought that was the problem. My spouse, also with the iPhone 6, has never had an issue with his.
Other issues developed with the phone, which ultimately ended up being hardware and the phone was replaced 4 months after I bought it. Hardware issues involved the wifi antenna, which died a slow death until it quit entirely, and the bluetooth, which died totally along with the wifi. At the time, I didn't connect the touch ID to all of that, but after having replacement phone #2 and having a properly functional touch ID for the first time, I do think my touch ID was faulty from the start. As it was with phone #2...although I was still blaming dry skin.
Yesterday morning, when I woke up, my phone asked for the passcode. I thought it had restarted during the night. This is what my first defective iPhone was doing when the hardware issues started, so I was alarmed. But now that I think about it, I don't recall seeing that message on the screen, only that the passcode was needed to enable touch ID. My spouse says his does that every couple of days or so as well, so I guess it's not a big deal. My other two iPhones never did, probably because I had to reset the touch ID so many times that it never had the chance.
It looks to me like the whole touch ID technology still needs some fine tuning.

MiniGeek: Thanks for your info & feedback. No one I know has had my issues. I do know that one has to put in the passcode periodically but my issue with fingerprint ID is like your where it just stops working at all & with all prints. Curious about your wifi issue as there have been some strange wifi issues with me too, although not very often. How did you become aware? I'll just keep trying with Apple about this. Sigh...