Changes to Touch ID warning after restarting iPhone due to unresponsive app This morning I restarted my iPhone 7 due to an unresponsive app - Facebook, which does not use Touch ID. On restart I had to enter my passcode, which was to be expected after a reboot. 

I then tried to view some banking apps, which require Touch ID, the first required my passcode, rather than Touch ID, I thought this was strange, but carried on. The second banking app showed a Touch ID error. Going back to the first app showed the error below. 

I have not made any changes to Touch ID since setting up the phone months ago (at which point I filled all 5 slots for fingerprints), so am slightly concerned about this warning. 

What could have caused this message? And what is the safest course of action?
This looks to be an issue with your bank's app. If I remember correctly, apps are notified anytime a touchID change is made, so things like 1Password will request your Master Password to sign in. This popup seems to be of your bank's design, and a software glitch made your phone think there was a change in TouchID.

For future reference, you can confirm that all fingers enrolled in touchID are yours by going to Settings > Touch ID &amp; Passcode. Then scroll to the part of the pane where it shows your touchID fingerprints:



Now, put each registered finger on the sensor and wait until the fingerprint is highlighted, like so:



Ensure that each fingerprint is yours by making sure that your fingers highlight all of the fingerprint options.

Or, you could just set touchID up again for all your fingers.