Q: Touch ID not working and unable to add fingerprint after updating to iOS 8.4.1

Follow these steps. Try again after each step:

1. Make sure that your fingers and the Home button are clean and dry.¹ For the Home button, use a clean, lint-free cloth to wipe off any dirt or debris.
2. Your finger should cover the Home button completely, touching the surrounding metal ring. While Touch ID is scanning, you shouldn't press down hard, tap too quickly, or move your finger around.
3. If you're using a case or screen protector, make sure it doesn't cover the Home button or the surrounding ring.
4. Tap Settings > Touch ID & Passcode. Make sure that iPhone Unlock or iTunes & App Store is on, and that you've enrolled one or more fingerprints.
5. Try enrolling a different finger.
6. If you can't enroll any of your fingers, take your device to an Apple Retail Store or Apple Authorized Service Provider, or contact Apple Support.

Use Touch ID on iPhone and iPad - Apple Support

i have the same problem from i update to ios 8.4.1 apple needs to fix this prob asap