How to set up a fingerprint scanner on Xiaomi Redmi Note 9: full instructions with nuances

The fingerprint scanner on the Xiaomi Redmi Note 9 is not just a convenient way to unlock, but also an additional layer of personal data protection. However, many users face problems when first setting up: the device does not recognize the finger, the sensor does not respond, or the system emits an error “Can not add a fingerprint”, most often due to improper finger preparation, sensor contamination or outdated MIUI firmware.

In this article, we will look at all the steps of setting up, from basic fingerprint addition to solving common errors, how to place your finger on the sensor, what security settings affect the scanner, and what to do if the Redmi Note 9 has stopped recognizing previously saved prints, and also hidden chips that are not written about in official instructions (for example, how to accelerate unlocking or add a fingerprint for specific applications).

If you’ve just purchased a Xiaomi Redmi Note 9 or reset it to factory settings, it can take 2-3 minutes to set up your fingerprint, but even experienced users sometimes miss important details — like not updating the software before adding a fingerprint or trying to register a wet finger — which can make the unlocking process uncomfortable or impossible.

Preparing the smartphone before setting up the fingerprint

Before adding a fingerprint, make sure your Redmi Note 9 is ready for it, and skipping at least one step can cause the sensor to malfunction or fail to save the fingerprint.

First, check out the MIUI version. The fingerprint scanner on this model only works stably on MIUI 12 firmware and later. If you have an older version, upgrade the system:

1. Go to Settings → About the phone → System update.
2. Click on "Check Updates" and install the latest version available.
3. Restart the device after the update.

Second, clean the fingerprint sensor of fat, dust and moisture, which is located on the back of the smartphone, under the camera. Use soft lilaless fabric (for example, for glasses) and a little alcohol. Do not use abrasive materials or liquids with acetone - they can damage the protective coating of the sensor.

Also make sure that:

• 🔋 There is enough charge on the smartphone (minimum 20%).
• 👆 The finger you will be registering is clean and dry.
• 🔒 The device is installed. PIN-code, pattern lock or password (without them, you can not add a fingerprint).

Clean the sensor of dirt and fat |

Update MIUI to the latest version|

Install PIN-code|

Charge your phone at least 20% |

Wash and dry hands-->

Step-by-step: how to add a fingerprint

Now, let's get to the process. Follow the instructions carefully, even a slight deviation (for example, taking a finger too quickly) can lead to incorrect fingerprint registration.

1. Open Settings and go to Password and Security.

2. select a fingerprint (if this item is missing, then your device is not installed). PIN-Code or Password – Go back to the previous section).

3. Enter the current one. PIN-proof-code.

4.Tap Add Fingerprint and follow the prompts on the screen.

An animation will appear on the screen that tells you how to place your finger, and here are some tips for perfect registration:

• 👆 Press your finger tightly but without pressing hard – the sensor should feel the skin texture, not the pressure.
• 🔄 Raise and lower your finger only when the system is commanded (when the screen flashes or vibrates).
• 🎯 Try to cover the entire area of the sensor, not just the center.
• ⏱️ Take your time – the slower you move your finger, the more accurate the fingerprint will be saved.

The system will ask you to apply your finger several times at different angles to capture it completely, and when the process is complete, you'll see the message "Print added," and you can unlock your phone by just touching the sensor with your finger.

Always, that's my main way.|

Only sometimes when it's convenient |

I used to, but now I've turned it off.|

I tried it, but I couldn't set it up.|

Configure additional parameters of the scanner

By default, the fingerprint on the Redmi Note 9 is used only to unlock the screen, but other useful features can be activated in the settings:

1. Unlock applications. You can protect individual programs (for example, banking or instant messengers) with a fingerprint:

- Open Settings → Applications → Blocking applications.

Select the right applications and activate fingerprint protection.

2. Payment via NFC. If you use Mi Pay or other payment systems, you can attach a fingerprint to confirm transactions:

Go to Settings → Connected Devices → NFC.

- Turn on the "Fingerprint Payment" option.

3. Quick unlock. To speed up the sensor, turn off the animation in the settings:

Go to Settings → Display → System Animation.

Select "No animation" or "0.5x".

You can also set up the fingerprint menu:

• 🔒 Vibration when unlocking (useful if you want tactile feedback).
• 📱 Unlock in sleep mode (finger will fire even when the screen is off).
• 🔄 Removing old fingerprints (if the sensor no longer recognizes the finger).

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If the scanner doesn't work well in winter, try adding the same fingerprint a second time at a different angle, which will improve recognition accuracy in cold weather when the skin becomes drier.

Common Mistakes and How to Fix Them

Even after you set up the fingerprint scanner on the Redmi Note 9, it can be unstable, and let's look at some of the most common problems and their solutions.

1.The sensor doesn't respond to touch

• 🔌 Restart your phone – sometimes a simple reboot helps.
• 🧼 Wipe the sensor and finger with an alcohol wipe.
• 🔧 Check if there is a film or cover covering the sensor.
• 📱 Remove the current print and add it again.

2.The system says "failed to add a fingerprint."

• 🔄 Try the other finger – perhaps there are too few unique lines on the chosen one.
• 📲 Update. MIUI Up to the latest version (see section "Preparation").
• 🔋 Make sure the battery is above 15% – with a low charge, some features are turned off.

3. The fingerprint is only recognized with a few attempts

• 👆 Add the same finger twice at different angles.
• 🧴 Apply a thin layer of hand cream on your finger – this will improve contact with the sensor.
• 🔧 In the fingerprint settings, disable the “Improved Recognition” option (sometimes it interferes with the settings).

If none of these methods worked, the problem may be a hardware fault with the sensor, in which case, contact Xiaomi Service Center, which can lead to a loss of warranty.

Comparison of the fingerprint scanner on the Redmi Note 9 with other Xiaomi models

The fingerprint sensor on the Redmi Note 9 is one of the second-generation optical scanners that appeared in Xiaomi’s budget smartphones in 2020, which is inferior in speed and accuracy to flagship ultrasonic scanners (for example, in the Mi 11 Ultra), but surpasses the first optical sensors (as in the Redmi Note 7).

The table below compares key characteristics:

As you can see, the Redmi Note 9 sensor is not the fastest, but it is accurate enough for everyday use, and its main disadvantage is its sensitivity to moisture and pollution, so it is important to monitor the purity of the finger and sensor.

If you use your smartphone frequently on the street or wearing gloves, consider alternative ways to unlock (such as facial recognition or Smart Lock).

Alternative ways to unlock if the scanner is not working

If your fingerprint is no longer recognized or the sensor is out of order, don’t despair – the Redmi Note 9 has a few backup options:

1. Facial recognition (Face Unlock)

- Fast and convenient, but less safe than a print.

- Settings: Settings → Password and security → Face recognition.

- Minus: It doesn't work in the dark and with a mask.

2. Smart Lock (Smart Lock)

Automatic unlocking in trusted places (home, work) or when connected to trusted devices (earphones, smartwatches).

Settings → Password and security → Smart Lock.

3. PIN-code

- Reliable, but not as comfortable.

Tip: Use a 6+ character digital PIN – it is safer than a pattern lock.

4. Voice unlock (via Google Assistant)

Suitable for unlocking in the car or at home.

- Settings: Settings → Google → Voice settings → Voice unlocking.

If you are temporarily unable to use a fingerprint (for example, because of a cut on your finger), combine these methods, for example, at home you can use Smart Lock, and on the street you can use facial recognition. + PIN-code.

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A fingerprint is the safest way to unlock, but it's not the only way. Always set up a backup method (PIN or password) in case the sensor fails.

Frequent User Questions (FAQ)

If your question isn’t on the list, check out Xiaomi’s official documentation or contact the Mi Community app for support.

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To speed up fingerprint unlocking, turn off animation in the developer settings. To do this, go to Settings → About Phone → MIUI Version (click 7 times), then to Settings → Additional → For Developers → The scale of the window animation (turn off).