I had this problem today on my iPhone 6S running iOS 11.2.2. I had left my device off overnight, on charge. When powering back on this morning my Touch ID fingerprints and all my messages were gone. A search did not refresh the messages. Turning the phone off and on again did not refresh them. After reading this thread I was inspired to try the following:
- Turned on flight mode.
- Closed all apps one by one by double tapping home button and swiping them up off the screen.
- Pressed and held power button for 5 seconds, then pressed and held home button for 5 seconds.
- Opened the Settings app to the Wallet and Apple Pay screen. I do not use Apple Pay. Double-Click Home Button was enabled, and I changed this to disabled.
- Pressed and held power button for 5 seconds and proceeded to power the device down.
- Powered the device back on and the messages were all back to normal, and Touch ID worked again.
I doubt that all steps were required, but it solved the issue and all of messages and touch ID are back to where they were.