The sudden failure of biometric unlock on Xiaomi’s smartphone is a problem that thousands of users around the world are facing. A device that opened in a split second with a light touch today ignores a finger or emits a read error. It’s not just an inconvenience that requires constant password input, but also a signal that a security or hardware system has failed, requiring immediate attention.
The reasons range from the cluttered surface of the sensor to serious problems with the motherboard or plume. Redmi and Xiaomi owners often notice that the scanner stops responding after a system update, a device drop, or even without visible external influences. Understanding the nature of the malfunction is the first step to successfully restore functionality without going to the service center.
In this article, we will look at all possible failure scenarios, from MIUI software glitches to physical injuries, how to diagnose correctly, what settings can block the sensor and in which cases an engineer will need to intervene, and the main thing is not to panic, since in most cases the problem is solved by software methods or simple cleaning.
The main reasons for the failure of the fingerprint scanner
The first thing to understand is that a fingerprint scanner is a complex module that depends on many factors. If Xiaomi has stopped working the print, most often the software is to blame. The MIUI or HyperOS operating system can conflict with sensor drivers after a failed update or installation of a “heavy” third-party launcher. Software failure is the most common and, fortunately, the most easily remedied cause.
The second important aspect is the physical condition of the surface: a protective glass or film pasted on top of the scanner can distort the signal, especially if it is thick or metallic, even minor contamination, greasy spots or moisture can disrupt contact. The scanners (optical) built into the screen are particularly sensitive to the quality of the protective coating and the cleanliness of the display.
⚠️ Note: If your phone has recently fallen or been hit, the problem may be in the departed plume, in which case software methods may not help, and you will need to disassemble the device to check the connection module.
Also worth considering is the effect of temperature. When the case is heated or cold, the sensor sensitivity can drop. This is temporary, but it often confuses users. In addition, some system applications or antiviruses can block access to biometric data for security purposes, which looks like a complete failure of the function.
Diagnosis: software failure or breakdown
Before you can carry your phone for repair, you need to do an initial diagnostic, and the easiest way to know if the sensor is alive is to check its response on the engineering menu or through the standard settings. If the phone vibrates when it touches but doesn't unlock, the problem is probably software, and if the screen doesn't even light up or respond to touch in the sensor area, it could be hardware.
For deep testing, you can use special codes to log into the engineering menu, which is a hidden interface designed to test the components of the device, and you can run an automatic scanner test to see if the system sees the device and transmits data, which is a critical step before any manipulation of data.
Pay attention to the behavior of other biometric features. If you have Face Unlock set up, check if it works. Often, problems with one security module don't affect others, which helps to localize the malfunction, and it's worth checking whether the fingerprint works in third-party applications, such as bank clients or instant messengers.
The table below gives the main symptoms and their probable causes, which will help you to orient yourself faster:
| Symptoms. | Probable cause | Difficulty of solution |
|---|---|---|
| Sensor doesn't respond to touch | Disabled plume or breakage of the module | High (requires repair) |
| He writes "failed," but vibrates. | Pollution or software failure | Low (cleaning or rebooting) |
| It only works with a certain finger. | Poor quality of print recording | Low (re-recording) |
| Stopped working after the update | Bug version MIUI/HyperOS | Medium (reset or wait for a patch) |
Basic settings and system reboot
The simplest and often ignored solution is to completely reboot the device. In Android-based operating systems, the processes responsible for biometrics can freeze in the background. Simply turning off and on the phone clears RAM and restarts all system services, including scanner drivers.
If a simple reboot didn't work, it's worth checking the scanner's settings. Sometimes users accidentally turn off the unlock function, leaving only the use of the fingerprint for payment or authorization in applications. You need to go to the settings menu and make sure the switch is active. The path to settings usually looks like this: Settings → Passwords and Security → Unlock by fingerprint.
☑️ Basic settings check
In the same menu, remove all previously stored prints and write them back. When you re-write, try to grab the edges of your finger and change the angle of inclination to create a more complete digital profile, which often solves the problem when the phone forgets the fingerprint or confuses it with another.
You should also pay attention to the "High Sensitivity" mode, if it's available in your firmware version, which is specifically designed for use with protective glass. If you have glass glued, enabling this feature can dramatically improve sensor responsiveness.
Problems after MIUI update and HyperOS update
Updating the operating system is always a lottery. Xiaomi developers are constantly improving security, but new versions of the MIUI or HyperOS shells can contain bugs that disrupt the operation of security modules. If the print stopped working immediately after the update, there is a high probability of driver version conflict or damage to system files.
In such cases, cleaning the cache of the Security app or the system cache in general helps, but if the problem is deeper, it may require a complete factory reset, a radical method, but it eliminates software errors accumulated during the use of the device.
⚠️ Note: Before performing a full reset (Wipe Data), be sure to back up all important data to a cloud server or computer, as all information from the phone will be deleted irretrievably.