TouchID not working while iPhone plugged in

....ok that was weird. I had always unlocked by Touch ID and charged my phone at the same time. But today I was in the dinning room with my phone plugged into a gfci circuit at the bar. Went to unlock and it would not even attempt to scan my print. The one time it did, it failed. After many searches I notice a lot of people had the same issue. I just plugged my phone in upstairs and Touch ID worked flawlessly. I thought to myself maybe the gfci circuit is the culprit. Tested in the bathroom and no Touch ID. Back in the bedroom Touch ID works. Have not tried with any other charge than what came in the box. Anyone else notice this?

This is an easy fix. With many cases the problem is in grounding the phone when charging, you will see that the phone will work normally case-less while charging, but a quick fix to this issue is to put aluminum foil preferably double stacked between your case and the bottom of the iPhone, this will allow your phone to be grounded while charging on an iPad charger.

Hi all,

I've got the same issue yesterday. I was surprised! Before, I never have had this issue and I was very heppy with my iPhone 6s, but yesterday, suddenly, I got my device without ability to unlock it while it charging.

Cable is 14 month's the same. Will try to replace it. However, I've just noticed, that I can successfully unlock the phone while I'm charging it from powerbank, without AC connected.

Try doing a reset. A reset will often clear glitches. To reset, press and hold both the Sleep/Wake and Home buttons for at least 10 seconds, until you see the Apple logo. You won't lose any data.

Sorry for not getting back to you sooner. As the phone is brand new it could be a hardware issue. I suggest you return it to the store and have it examined.

I'm having this same issue running 8.1.2. I recently noticed that sometimes when I pick up my iphone 6+ from the desk the touch ID does not open the phone. When it gets into this mode, it simply ignores when I put my thumb on the sensor. However, it works immediately as soon as I unplug the phone from the charger each and every time so far in my experimentation. I haven't figured out exactly what triggers this situation yet but it happens enough to have become a hassle. I assume it's a software issue/bug that hasn't yet been widely recognized.

I updated my post above but for some reason the system wouldn't let me re-edit my comments above so I'm posting my update below:

I'm having this same issue running 8.1.2. I recently noticed that if I pick up my iphone 6+ while it's plugged in the touch ID does not open the phone. However, it works immediately as soon as I unplug the phone from the charger each and every time so far in my experimentation. I've been able to recreate this situation by plugging in the phone and waiting a few minutes. After a few minutes, if I pick up the phone and unlock it with my finger print the touch ID is not unresponsive. Well, some are saying it can be caused when you are not plugged in through Apples inverter and in my case I'm plugged into an after market power strip USB port that is on my desk. I'm going to bring in the apple inverter and plug into that instead and see if the problem goes away. I'll try to report back.

Here are the results from my testing. As stated previously, I was plugged into a USB port on an after market power strip and discovered that the touchID sensor would not work while the iPhone is plugged in. I brought the little square power adapter that comes with the iphone to the office and plugged it into the same power strip and then the phone into that. Now the touchID sensor works perfectly when the phone is plugged in. Go figure. At least for me, problem solved... If you have a similar issue, try plugging in through the apple supplied 120V adapter and this may solve your problem too.

I found a fix for me. I have the same problem, either with an Apple charger or a third party one. But then I tried using a few different household extension cords to experiment. I found that with my longer 15 foot extension cord the touchID works fine! I noticed the shorter cords had the problem. So try a longer extension cord. Perhaps the length does something to change the current by the time it gets to the phone, reducing interference.

I have this issue too on my iPhone 5S and to me it appears it's simply a bad cable. The cable I am using is the standard issue Apple Lightning cable that comes with the phone. I switched over to the cable my wife is using for her iPhone 6S, which is also standard issue with her phone, and I was once again able to use Touch ID with the phone plugged in.

Hey everyone,

So the reason why your touchIDs are not working while plugged in is that there is an interference between the finger sensor and your finger. This interference is caused by the electric field generated by the charging solenoids (conductive lines) which route from the port to the phone battery. Apple designed the 5s/6/6+/6s/6s+ device's all with the sensor directly above the charge port. The finger print sensors are designed to measure where the unique electrical conductances are passing between your finger print tracks. This is a very sensitive task when using micro electronics. Any small amount of electro magnetic interference can cause a disruption in the pattern, hence distorting your finger print reading.

Your finger print is not ignored, it is just reading incorrectly. Multiple attempts will eventually lock out your phone and require a passcode entry. Also, try establishing a touchID while your phone is plugged in. It may eventually pass if you're lucky but all of my attempts failed. This may be caused by the lack of interference protection on your particular device from a defect in manufacturing or just because it is a bad design that has not been changed for over 4 years. I can't recommend design changes on here due to copyright policies.

I had the 5s and now a 6s, and still no change in the issue. I recommend you not bother with the hassle of exchanging phones if this is your only "problem." Getting a "new" one will either replace your current problem with the same one, or worse, new one's. It is possible to hopefully get the current flowing into your device low enough such that the electric field can be reduced to a level in which the interference is negligible which is why some people are experiencing a working touchID while plugged in using the same OEM Apple lightning cable and AC-DC converter (100-240VAC to 5VDC @ 1A). It all depends on how the converter can manage the outlet Voltage and Current. At this point, is it more worth it to rewire your home, fly to other cities, or even search endlessly for a manageable wall outlet, or just live with the device you paid for. Often times they will have you reset, reformat, or return your device, but frankly those are just band aids to the real problem.

Also I just realized that when the phone is near fully charged (95%), the touchID worked while plugged in. Once again though, this could be due to the low current being drawn from the battery as it reaches max charge. Since batteries act similar to capacitors, current approaches 0A as time goes to infinity when charging a battery.

i tried a few suggested solutions but nothing seemed to work until i took the silicone case off and then it worked perfectly when plugged in. Sometimes with the case on it works when plugged in but its pretty rare and seems to depend on where my other fingers are placed. I couldn't find a consistent solution other than to remove the case. NO need to call the electrician or buy new cables as suggested in other posts. Interference indeed mr Turner !

I see this problem with a new iPhone 7 and also my wife's 6+. I'm reproducing it right now with the 7 plugged in with an Apple cable to the USB port on my iMac. If you go to Settings>Touch ID and passcode you can watch your fingerprint entries "light up" as they register. Try this: set the phone down and only touch the ID sensor with your finger...it will only register like 1 in 10 tries. Now: touch an exposed metal part of the phone with your other hand and use your finger on the sensor....it should work perfectly. You need to be grounding the phone for the touch ID to work due to electrical interference at the charge port (as Josiedoesit explains above). This also explains why people with full cases experience this issue more, less metal to touch. Try and find an exposed switch or the Apple logo on the back to touch with one hand as you activate the Touch ID when the phone is plugged in. I was nearly ready to take this phone back to Apple for replacement when I searched up this thread and it all clicked into place.