Why does not work fingerprint Xiaomi: all the reasons and ways to fix

The fingerprint scanner on Xiaomi, Redmi and POCO smartphones is one of the most convenient ways to unlock, but sometimes it stops working for no apparent reason. It doesn't recognize touch, it gives an error "I couldn't read the print", it doesn't respond at all. In 80% of cases, the problem is solved independently without going to the service center. In this article, we will analyze all possible causes, from the banal (dir on the sensor) to the technical (damage of the plume), and give step-by-step instructions for restoring.

It is important to understand that the scanner algorithm depends on the type of sensor: ultrasonic (installed in flagships, for example, Xiaomi 13 Ultra), optical (under the screen, like in the Redmi Note 12 Pro+) or capacitive (physical button on older models like Redmi 5 Plus).

If your smartphone is in the water, dropped from a height or was repaired, immediately go to the section on hardware malfunctions. In all other cases, start with software methods: they are free and do not require disassembling the phone.

Top-5 Reasons Why Xiaomi’s Fingerprint Doesn’t Work

According to service center statistics, 9 out of 10 scanners fail because of software failures or incorrect settings.

• 🧼 Sensor pollution: fat, sweat, dust, or protective film block the reading of a fingerprint, especially for optical scanners under the screen.
• 🔄 Failure of MIUI: After a system update or reset, the biometrics module may shut down.
• 👆 Incorrect fingerprint registration: scanning too fast or incomplete when adding a finger.
• 🔋 Battery savings: In super-saving mode, the scanner can shut down to reduce power consumption.
• 🛠️ Sensor or plume damage: After falling, moisture or unskilled repair.

Before you bring your phone to the service, check all the items on this list, and let's start with the simplest one: cleaning the sensor.

How to Clean Your Fingerprint Sensor on Xiaomi

The optical and ultrasound scanners built into the screen are particularly sensitive to contamination, and even a thin layer of fat or micro-scratches on the protective glass can block the reading.

• 🧴 Alcohol wipes (70% isopropyl alcohol) or wet wipes for machinery.
• 🧻 Soft lilac-free fabric (microfibra).
• 🔦 Lantern (to check cleanliness)

Cleaning instructions:

1. Turn off your smartphone to avoid accidental taps.
2. Gently wipe the sensor area with an alcohol napkin without pressing (especially if the scanner is under the screen).
3. Remove moisture residues with a dry microfiber.
4. Check if there are any scratches or chips on the sensor (if any - see the section on hardware damage).

If the scanner still does not work after cleaning, try to re-register the fingerprint - sometimes the old data conflicts with the updated firmware.

⚠️ Warning: Never use abrasives (such as toothpaste) or hard tissue to clean the sensor, which can damage the protective coating and render the scanner inoperable.

Software methods for restoring the scanner

If the sensor is clean, but the print is still not being read, the problem is the software.

1. Phone reboot

It's banal, but it works 30 percent of the time. → Reboot. Check the scanner when it's on.

2.Update MIUI

Go to Settings → About Phone → System Update. If a new firmware version is available, install it. Often updates fix biometric bugs.

3. Reset scanner settings

Go to Settings → Passwords & Security → Fingerprints and delete all saved fingerprints. Then add them again, following the instructions on the screen.

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When registering a fingerprint, press your finger tightly, but without pressing hard. Repeat the process 3-4 times for one finger, this will improve the accuracy of recognition.

4. Cleaning the system cache

Go to Settings → Applications → Application Management → Three dots (menu) → Show system. Find BiometricService (or similar), clear the cache and data.

5. Reset all settings

If nothing works, do a soft reset (without deleting data): Settings → Additional → Settings Reset → Reset network settings / all settings. This will return the biometrics to factory settings.

If after all the manipulations, the scanner never worked, the problem is probably hardware.

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Before resetting, back up your data via Settings → Additional → Backup. This will save your photos, contacts and messages.

Hardware malfunctions: when to carry in the service

If the software methods didn't work, it's likely that the sensor itself or the connection to the motherboard has been damaged.

• 💥 The scanner stopped working after a fall or impact.
• 🌊 The phone was caught in rain or water (even if it dried up later).
• 🔧 Recently, a repair (screen replacement, battery replacement) was carried out.
• 🔍 The sensor is externally damaged (cracks, dents, oxidation marks).
• 🔌 The phone does not respond to any fingerprints, even after re-registration.

The critical point is that if the scanner stopped working after the screen was replaced, 95 percent of the time, the fault is with the damaged plume of the sensor, and you can't repair it yourself, you need soldering equipment and experience.

To diagnose hardware problems:

1. Try to register the fingerprint of the other finger – if it does not work, the sensor is faulty.
2. Connect your phone to your PC and check logs through adb logcat (there must be errors like FingerprintHal: Failed to open device).
3. If the phone is warranty - contact the official Xiaomi service.The cost of replacing the sensor is out of warranty: from 1,500 to 5 000 rubles (depending on the model).

⚠️ Warning: Do not attempt to disassemble the phone yourself unless you have experience with microelectronics. Damage to the sensor plume or motherboard can result in a complete loss of service.

Features of scanners on different models Xiaomi

Biometric authentication technologies on Xiaomi devices vary depending on the price segment and year of release.

On Xiaomi Mi A3 and other Android One devices (without MIUI), the scanner may fail after updates due to conflict with Google services.

1. Removing updates for Google Play Services.
2. Reverse to factory firmware via Fastboot.

The POCO F3/F4 with an ultrasonic scanner has a false positive problem, which unlocks the phone from random touches, and can be fixed by disabling the option of Enhanced Recognition in the fingerprint settings.

How to replace your fingerprint if it doesn’t work

While you are looking for a solution or waiting for repairs, you can use alternative ways to unlock:

• 🔐 PIN-code or pattern lock: the most reliable option, but less convenient.
• 👤 Face recognition (Face ID): works on most Xiaomi models (except budget ones).
• 🔑 Smart Lock: Automatically unlock in trusted locations (home, work) or when connected to a trusted device (e.g., smartwatch).
• 📱 Temporary Password: Some models (e.g., Xiaomi 13 Pro) support one-time unlock codes.

To enable Face ID:

1. Go to Settings → Passwords and Security → Face Recognition.
2. Follow the instructions on the screen (you will need to register the face from different angles).
3. In the security settings, set Unlock the lock screen.

To set up the Smart Lock:

1. Go to Settings → Passwords and Security → Smart Lock.
2. Add trusted devices (such as Mi Band) or places.
3. Activate the option Reliable devices.

⚠️ Facial recognition is less secure than a fingerprint. An attacker can unlock the phone with your photo (especially on budget models without a photo). 3D-Don't use Face. ID for authorization in banking applications.

How to Prevent Scanner Problems in the Future

To make your fingerprint work on Xiaomi, follow these guidelines:

• 🧴 Clean the sensor regularly (every 2 weeks) with a soft cloth.
• 🚫 Avoid installing thick protective glasses — they may block the optical scanner.
• 🔋 Do not discharge the phone to zero, as this can cause malfunctions in the biometric module.
• 🔄 After updating MIUI, always re-register the prints.
• 🛡️ Do not install custom firmware (like LineageOS) — they often break the scanner.

If you are often outdoors or work in dusty conditions, use covers with a cutout under the sensor and periodically blow the connectors with compressed air (without alcohol!).

For POCO and Redmi owners with capacitive sensors (button): avoid pressing the button hard, as this can damage the micro-switch inside.

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The most common cause of scanner failure is mechanical damage, and even a small crack on the screen above the optical sensor can make it inoperable.

Frequent Questions About Xiaomi’s Fingerprint Scanner