The Samsung Galaxy S21 comes with a pre-installed screen protector that perfectly works with the device’s under-display ultrasonic fingerprint sensor. But a lot of us prefer installing a stronger screen protector (also called tempered glasses) to protect our device’s display and screen.
However, some users have complained that it is difficult and sometimes almost impossible to use the fingerprint scanner with the screen protector installed. They say the scanner cannot detect their fingerprint.
This can happen due to an incompatible screen protector, a protector covered with moisture, dirt, or debris, and extreme temperature conditions.
To address this issue, we have created this guide including practical solutions with easy-to-follow instructions. All you have to do is follow the instructions correctly and fix the fingerprint working again.
Note: Solutions in this guide will work on any Samsung Galaxy S21 model (S21, S21 Plus, S21 Fe, and S21 Ultra models.)
Editor’s note: We created these instructions using a Samsung Galaxy S21 running Android 13. Depending on your device’s software version, some steps and menu positions may look slightly different.
Fix 01: Clean the Screen Protector
One of the main reasons why the fingerprint scanner not working is dirt, debris, or smudges on the screen protector These particles can hinder the under-display ultrasonic fingerprint scanner functionality, causing unsuccessful unlock attempts.
To clean your screen protector, follow these simple steps:
- Power off your Galaxy S21.
- Use a microfiber cloth to gently wipe the screen. This cloth is soft and ideal for cleaning delicate surfaces like your phone’s screen.
- Wipe the screen in a circular motion, paying extra attention to the area where the fingerprint scanner is located.
- Once the screen is clean, allow it to dry completely before turning your device back on.
Fix 02: Check If the Screen Protector is Compatible With Your Device
The fingerprint sensor/scanner on your Samsung Galaxy S21 uses ultrasonic waves to accurately recognize your fingerprint but certain screen protectors with thick or multiple layers can disrupt the ultrasonic waves, causing failed attempts or slower recognition.
You can check your screen protector compatibility by referring to the product description or manufacturer, and certain screen protectors labeled as being compatible with the in-screen fingerprint scanner for S21.
If your screen protector is damaged, such as scratches or cracks, it also affects the scanner’s ability to read fingerprints.
In these cases, replacing the screen protector will resolve the issue.
Fix 03: Re-Register Your Fingerprint
If you just got the screen protector installed or have changed it recently, it can cause the scanner not to match the initial registered fingerprints.
Re-registering your fingerprints will fix this issue as it allows your device to adapt to the new screen protector and accurately read your fingerprints.
This is how to do it:
- Go to Settings on your Galaxy S21.
- Scroll down and tap on Security and privacy.
- Tap on Biometrics.
- Enter your current security (PIN, pattern, or password).
- Tap and hold to select the existing fingerprint.
- Remove to delete the existing fingerprints.
- Once you have removed all the fingerprints, tap on Add fingerprint.
- Follow the on-screen instructions to register your fingerprint again.
Fix 04: Use a Compatible Screen Protector
If your fingerprint scanner still doesn’t work after trying the above fixes, It’s good to Install a new screen protector by removing the old one by following the instructions and trying to use the fingerprint scanner again.
Make sure to purchase a Samsung-certified screen protector for your Galaxy S21, as these protectors are compatible with the in-screen fingerprint scanner.
Wrapping Up
The in-screen fingerprint scanner on the Samsung Galaxy S21 is an advanced feature for secure device unlocking. However, issues can arise when the screen protector is incompatible, dirty, or damaged.
But with the help of our guide, we hope you have sorted the fingerprint scanner issue on your S21. If you have any questions regarding this guide, simply leave a comment below. We will be there to assist you.
