Q: Touch ID being Erratic

HR2D: Have you read through this thread and seen the pic I posted a few pages back which shows what part (the very end) of your finger to avoid? I think you'll find that's the cause of the problem you're having. Also, install IOS 7.0.3 if you haven't already.

Mine is exactly the same. Sometimes you dont get a Touch ID response or message, just the slide to unlock text.

Happends like that to me too. Seems to have started over the past couple of days.

This has started happening to my phone as well.  Touch ID doesn't even register that my finger is there.  The only option I get to unlock is to slide and input my passcode.  Then when I lock the phone, Touch ID starts working again.  Seems to have occured once the last couple of days.  Don't know if it's 7.0.3 or something else.  I've had my 5S since launch and never had this problem before.

Went to Apple store yesterday and the tech said that I should reset my iphone 5S and so far that has cured my touch ID issue (it would not hold for more than 1 day).  Settings>General>Reset>Reset All Settings

Sounds like a variation of the problem I was having under 7.0.2.  Since it has worked fine for you since launch it's probably not an issue with the way you've registered the prints.  Sometimes apps crashing or a low memory situation can cause a failure.  Check your diagnostic and usuage log in settings to see if anything strange is going on.

EDIT: Actually, disrgeard that...just re-read the last few posts...I've also seen that just a couple times since upgrading to 7.0.3.  It looks to me like it's actually reading the print, but for some reason it doesn't immediately unlock, but you can slide to unlock without entering the code.  I don't think it's a security flaw becasue it does actually appear to read the print first.  It just seems like a minor glitch to me.

Message was edited by: mrsnork

I restarted the phone and as of yet, 24hrs, it has not happened again. This seems to be a software bug as locking the phone again and then using the sensor works straight away.

Yes, I am having this same issue.  Every 2-3 days I have to erase my old fingerprint and enter a new one.  My fingerprint works flawlessly (instantly, no effort, no careful placement of finger, all different angle placements each time).  Then it stops working well.  Maybe one out of five times (and only with annoyingly careful & methodical placement of my thumb).  I then erase, reenter, love the fingerprint ID for 2-3 days.  Hate it...and the dance continues.  Perhaps I am missing something, but I don't understand how it could EVER work so perfectly if it is an original fingerprint entry problem.  Also, I have ruled out lotions, etc. being the problem because 2 seconds after it working awfully for me I reenter my fingerprint and it is flawless...for awhile.  Argh!

One of the Apple sites states that TouchID is supposed to improve with usage.  Whether that means the fingerprint criteria is tightened or loosened (based on various positional readings), this seems to imply this is not a static operation from the initial read.  So here's a possible theory (swag)- suppose this is either corrupting the fingerprint scan data or tightening it beyond usability?   Just a thought, based on the symptoms that I see as well as quite a few others.

Here's the quote from this site: http://support.apple.com/kb/HT5949

Touch ID will incrementally add new sections of your fingerprint to your enrolled fingerprint data to improve matching accuracy over time. Touch ID uses all of this to provide an accurate match and a very high level of security.

Same problem here, except it stops working in hours. I just noticed something else, when I clicked my magic trackpad on the reply button, it failed to register and I had to hit it a second time. That makes me wonder if my fingers are too weak to get the needed pressure to trip the sensor. Maybe some of us just can't use it! Maybe we could learn by remaking them every time they fail and thereby building muscle memory. I suppose it's worth a try.

slewis, I'm curious if after 4 days, you're still not having to enter your passcode?

I've only had to put the password in twice, and both times in the morning.  Compared to before I wiped and recovered from backup (where I was putting my password in at least 1/3 of the time I was unlocking my phone), it's a lot better.

When it's working for me, I've only had one or two bad reads before it unlocks.  I think TouchID is very moisture sensitive; when there's a failed read, a wipe of the sensor and a careful finger choice seems to do the trick.

My current thought is that the hardware is working as expected and I have the wrong kind of fingers for 100% unlocking success :S

I would add:

1.  Install 703

2. Settings > General > Reset > Erase All Settings [this was suggested above]

3. Retrain using the instructions given by Apple here.

Step #2 followed by #3 seem really to have improved accuracy for me.

For me, unless I have just washed and dried my hands, I can't get it to read it. It just says time and time again to "try again" then it fails and asks for the passcode. My fingers get kinda sweay at times which I know is an issue for it but that fact that it doesn't work 3/4's of the time is really frustrating.

I've tried clearing all the finger prints and rescanning it, etc.