How to Fix Face ID or Touch ID When It Stops Working

2026-10-07 · Marion Phone Repair

You pick up your phone, look at it or press your finger to the sensor, and nothing happens — it does not recognize you. Biometric authentication (Face ID, Touch ID, fingerprint sensors, face unlock) failing is frustrating because it forces you to type your passcode every time. Most of the time the problem is not hardware failure. It is a software glitch, a dirty sensor, or changed conditions that the biometric system was not trained for.

Face ID not working on iPhone

Clean the TrueDepth camera

Face ID uses the front-facing camera system at the top of the screen. If the sensors are dirty or obstructed, Face ID cannot map your face:

• Wipe the top area of the screen (the notch on older models, the Dynamic Island area on newer models) with a soft, lint-free cloth
• Remove any screen protector that might be covering the sensors. Some thick or poorly aligned screen protectors block the infrared sensors Face ID depends on. If Face ID works without the protector, the protector is the problem — replace it with one designed for Face ID compatibility
• Check that nothing is physically covering the sensors — a phone case that extends over the top edge, a sticker, or residue from a removed protector

Check your face setup

• Face ID struggles with certain obstructions: large sunglasses that cover your eyebrows, face masks covering your nose and mouth (unless you set up Face ID with a mask), scarves wrapped high, or hats with low brims that shadow your eyes
• If you regularly wear glasses you did not have when you set up Face ID, or if you have significantly changed your appearance (new beard, different hairstyle that covers your forehead), consider resetting Face ID and setting it up again
• Go to Settings, Face ID and Passcode, enter your passcode. If Set Up an Alternative Appearance is available, add your current look as an alternative appearance. This lets Face ID recognize you in two different configurations

Reset Face ID

• Settings, Face ID and Passcode, enter passcode, Reset Face ID
• Then tap Set Up Face ID and follow the enrollment process. Move your head in a circle so the camera captures your face from all angles
• After setup, test Face ID in good lighting. It should recognize you immediately. Then test in dim lighting — Face ID uses infrared and works in the dark, but the initial test confirms the setup worked

Software fixes

• Restart your iPhone. Face ID depends on multiple software components, and a restart clears temporary glitches that can interfere with biometric processing
• Update to the latest iOS version. Settings, General, Software Update. Apple periodically improves Face ID reliability through software updates
• Check that Face ID is enabled for what you need it for. Settings, Face ID and Passcode shows toggle switches for iPhone Unlock, App Store purchases, password autofill, and individual apps. Verify these are turned on

Touch ID not working on iPhone

Clean the sensor and your finger

Touch ID reads your fingerprint through the Home button (iPhone SE, older models) or the side button (newer iPad models). The sensor needs clear contact with your finger:

• Wipe the Home button or side button with a clean, dry cloth. Oils, moisture, lotion, sunscreen, and dirt interfere with fingerprint reading
• Dry your finger thoroughly. Wet or sweaty fingers do not register reliably
• If you have a screen protector or case that covers or interferes with the Home button, remove it and test

Re-enroll your fingerprint

• Settings, Touch ID and Passcode, enter passcode
• You can have up to five fingerprints enrolled. If your current prints are not working, delete them (tap the fingerprint entry and tap Delete Fingerprint)
• Tap Add a Fingerprint and re-enroll. During enrollment, reposition your finger slightly with each tap to capture different parts of your fingerprint. Include the edges and tip — these are the areas Touch ID most often fails to read
• Enroll the same finger twice (using two of your five slots) for better reliability. Each enrollment captures slightly different parts of the print, improving overall recognition

Common Touch ID issues

• Callused or dry fingers: People who work with their hands, play guitar, or have dry skin may have fingerprints that are harder to read. Moisturizing your fingertips before enrollment can help. Enrolling the same finger twice also improves recognition for difficult prints
• Cuts or blisters: A cut or blister on your enrolled finger changes the print temporarily. Use a different enrolled finger until the skin heals, or temporarily rely on your passcode
• Cold weather: Very cold fingers have reduced blood flow, which can slightly change the fingerprint pattern and reduce moisture at the surface. Warm your hands before trying

Android fingerprint sensor not working

Under-display sensors

Many Android phones place the fingerprint sensor under the screen. These optical or ultrasonic sensors read your fingerprint through the display glass:

• Clean the area of the screen where the sensor is located. The sensor is usually in the lower third of the screen — look for an on-screen fingerprint icon when the phone is locked
• Remove any screen protector and test. Under-display sensors are particularly sensitive to screen protectors. Thick tempered glass protectors can block optical sensors entirely. If the sensor works without the protector, switch to a compatible protector (usually a thin TPU film for optical sensors)
• Press firmly. Under-display sensors often need more pressure than side-mounted or rear-mounted sensors
• Re-register your fingerprint. Settings, Security (or Biometrics and Security on Samsung), Fingerprints. Delete existing prints and add them again. During enrollment, cover the entire sensor area by shifting your finger position with each tap

Side-mounted and rear-mounted sensors

• Side-mounted sensors are built into the power button. Rear sensors are on the back of the phone. Both are capacitive sensors similar to Touch ID
• Clean the sensor surface with a dry cloth
• Make sure you are using the correct finger in the correct position. Side sensors are narrow — you need to center your finger on the sensor
• Re-enroll fingerprints through Settings, Security, Fingerprints

Android face unlock not working

• Most Android face unlock (except Pixel 4 and some Samsung models) uses the front camera rather than a dedicated infrared sensor. This means it is more affected by lighting conditions
• Face unlock on most Android phones does not work well in darkness because it relies on visible light
• Clean the front camera lens
• Re-enroll your face through Settings, Security, Face Recognition. Remove the existing face data and set it up again in good, even lighting
• Remove sunglasses, hats, or anything that significantly changes your face appearance

When it might be hardware

If none of the software fixes work, the biometric sensor may have a hardware problem:

• Face ID: If Face ID stopped working after a drop or screen replacement, the TrueDepth camera system may be damaged. Apple pairs the Face ID hardware to the logic board — third-party screen replacements sometimes disconnect or damage the Face ID components. A diagnostic check can confirm whether the hardware is functional
• Touch ID: If the Home button was replaced or repaired by a third party, Touch ID may not work because Apple pairs the Touch ID sensor to the secure enclave on the logic board. The button can still function as a button without Touch ID working
• Under-display fingerprint: If the screen was replaced, the sensor may not be properly aligned or connected. Screen replacements with aftermarket parts may have sensors that perform worse than the original
• Water damage: Moisture inside the phone can interfere with biometric sensors. If the phone was submerged or exposed to heavy moisture and biometrics stopped working afterward, internal corrosion may be affecting the sensor

Temporary workarounds

• Use your passcode or PIN while troubleshooting. Biometric failure does not lock you out — your backup authentication method always works
• If Face ID works intermittently, holding the phone at a slightly different distance (closer or farther) sometimes helps. Face ID works at roughly 10 to 20 inches from your face
• If your fingerprint sensor works intermittently, try enrolling a different finger that may have clearer prints

Need help with biometric issues?

If your Face ID, Touch ID, or fingerprint sensor has stopped working and the software fixes in this guide did not resolve it, the sensor hardware or its connection may need professional attention. Marion Phone Repair can diagnose whether the issue is software or hardware and get your biometric unlock working again.