The Samsung Galaxy S21/S21+/S21 Ultra series fingerprint sensor is bleeding-edge technology. Unlike traditional phones with optical scanners, it uses ultrasound to create an image of your fingerprint and even detect blood flow in your fingertips.
But this tech is still imperfect since the fingerprint sensor sometimes has issues and can stop working due to dirt, wireless charging, or software trouble.
In this guide, we’re giving you eight proven-and-tested solutions to fix the Galaxy S21/S21+/S21 Ultra fingerprint sensor issue. Plus, we’re putting up pictures and all the details you need to quickly get your S21 in tip-top shape — in 15 minutes or less.
Why is my fingerprint sensor not working?
Some of the common causes for the fingerprint sensor to not work are as follows:
- The fingerprint sensor may fail to recognize a wet or dirty finger.
- A finger that’s too dry may also be unrecognizable to the fingerprint sensor.
- You’re not using the entire surface of your finger on the sensor.
- The fingerprint sensor won’t work if the display is exposed to dirt and moisture.
- The phone was dropped, leading to a damage in the display screen or fingerprint sensor.
How to Fix the Fingerprint Sensor Problem on Galaxy S21, S21+, and S21 Ultra
Fix Samsung Galaxy S21/S21+/S21 Ultra fingerprint sensor issues by keeping the phone screen clean, using a compatible screen protector, and updating your fingerprint settings.
You can also fix them via a soft reset, hard reset, system update, and clearing the cache partition on your phone.
But that’s not all there is to it! Here’s a more detailed approach.
1. Restart the device.
| Difficulty Level | Easy |
| Time to Complete | 30 seconds |
| Number of Steps | 3 |
The first rule when troubleshooting a phone is always to perform a soft reset before anything else. This simple method involves only switching the device’s power off and then on again.
This allows you to fix minor problems by shutting down all instances of apps and processes running on your phone and refreshing the system afterward.
Follow the steps below to restart your device:
- Press/hold the side button.
- Tap Restart on the pop-up menu.
- Wait for the device to boot back up.
Once the device is fully booted, check to see if the fingerprint sensor is working.
2. Clean the screen.
| Difficulty Level | Easy |
| Time to Complete | 5 seconds |
| Number of Steps | 1 |
Believe it or not, the fingerprint sensor can stop working due to something as simple as a dirty display screen. Keeping your display clean at all times should be enough to fix Galaxy S21/S21+/Ultra fingerprint sensor issue caused by screen dirt.
According to Samsung, a soft and lint-free microfiber cloth is the best material for cleaning your device. Wipe the phone’s display gently until it’s clean.
Note: Make sure your fingers are clean as well. If you have sweaty hands, wipe them dry before scanning.
3. Use a compatible screen protector.
| Difficulty Level | Easy |
| Time to Complete | 20 seconds |
| Number of Steps | 1 |
The Samsung Galaxy S21 series comes pre-installed with a screen protector. Once it suffers any damage, it can result in your display’s fingerprint sensor not working properly.
For replacement, we recommend only using a Samsung-accredited screen protector.
Note: You can also choose to not use any screen protector. The Galaxy S21 uses Corning Gorilla Glass Victus which is durable and effective in preventing scratches.
4. Increase the touch sensitivity.
| Difficulty Level | Easy |
| Time to Complete | 7 seconds |
| Number of Steps | 3 |
Have you recently replaced the pre-installed screen protector on your Galaxy S21 device? If you did, depending on the quality and thickness of the replacement used, it may affect the display’s touch sensitivity and the sensor’s detection capability.
Follow the steps below to Increase your phone’s touch sensitivity:
- Open Settings.
- Click Display.
- Toggle Touch sensitivity on.
5. Remove and add fingerprints.
If you’re constantly experiencing failed attempts when scanning your finger, consider removing your registered fingerprint and adding it back again. This should reset your fingerprint setup and fix Galaxy S21/S21+/Ultra fingerprint sensor issue.
Use the following steps to remove fingerprints:
| Difficulty Level | Easy |
| Time to Complete | 15 seconds |
| Number of Steps | 7 |
- Open Settings.
- Scroll down/click Biometrics and security.
- Click Fingerprints.
- Input your PIN or Password.
- Press/hold any registered fingerprint to make a selection.
- Check all the fingerprints you want to remove.
- Click Remove.
Add fingerprints using the following steps:
| Difficulty Level | Easy to Moderate |
| Time to Complete | 20 seconds |
| Number of Steps | 7 |
- Open Settings.
- Scroll down/click Biometrics and security.
- Click Fingerprints.
- Input your PIN or Password.
- Click Add fingerprint.
- Click Continue.
- Follow the directions on the screen.
Pro tip: Registering two fingerprints for one finger is effective in preventing failed attempts when scanning.
6. Update the software.
| Difficulty Level | Easy |
| Time to Complete | 30 minutes |
| Number of Steps | 5 |
Software updates are paramount in ensuring that your device will run properly while also fixing any bugs and errors present in previous versions of the software. Doing so will also ramp up your phone’s protection.
Follow the steps below to update the software:
- Open Settings
- Scroll down/click Software Update.
- Click Download and Install.
- Click Install Now after the download is complete.
- Wait until the installation is completed.
7. Wipe the system’s cache partition.
| Difficulty Level | Moderate |
| Time to Complete | 3 minutes |
| Number of Steps | 11 |
The cache partition on your device is the storage for temporary data and settings from the applications on your phone. If the data gets corrupted, this can cause applications and features on your phone to malfunction.
Follow the steps below to wipe the system’s cache partition:
- Press/hold the side button.
- Tap Power Off on the pop-up menu.
- Wait for your phone to shut down.
- Use a USB cable to plug your phone into a PC.
- Press/hold the volume up button and the side button simultaneously.
- Hold until you boot into Recovery Mode.
Note: Press the volume buttons to highlight a selection. Press the side button to confirm a selection.
- Select Wipe cache partition.
- Press the side button to confirm.
- Select Yes and press the side button.
- Press the side button to confirm the Reboot system now.
- Wait until the device completely boots up.
8. Factory reset the phone.
| Difficulty Level | Moderate |
| Time to Complete | 15 to 20 minutes |
| Number of Steps | 13 |
Factory resetting is usually reserved as a last resort when troubleshooting. Unlike a soft reset, this method wipes the data and reverts the settings on your phone to its initial state after it was manufactured.
Before you proceed with this method, we recommend backing up your phone’s data on a PC or the cloud so you can restore it once the reset is complete.
Perform a factory reset using the steps below:
- Press/hold the side button.
- Tap Power Off on the pop-up menu.
- Wait for your phone to shut down.
- Use a USB cable to plug your phone into a PC.
- Press/hold the volume up button and the side button simultaneously.
- Hold until you boot into Recovery Mode.
Note: Press the volume buttons to highlight a selection. Press the side button to confirm a selection.
- Select Wipe data/factory reset.
- Press the side button to confirm.
- Select Factory data reset.
- Press the side button to confirm.
- Wait for the screen below to say “data wipe complete.”
- Press the side button to confirm the Reboot system now.
- Wait until the device completely boots up.
The factory reset should have deleted any corrupt data or files and removed any prior changes that caused the fingerprint sensor issue on your phone.
Wrapping Up
Being systematic can go a long way to fix Galaxy S21/S21+/Ultra fingerprint sensor issues. Start from the top solution and don’t skip a step to get going; otherwise, if the problem persists, consulting your nearest Samsung Service Center is wise.
Galaxy S21/S21+/S21 Ultra Fingerprint Sensor Issue FAQs
To use the fingerprint scanner on Samsung Galaxy S21, set up and register a fingerprint by going to Settings > Biometrics and security > Fingerprints > Add fingerprint.
The Samsung Galaxy S21 uses an in-display fingerprint sensor located on the phone’s screen. It’s ultrasonic using sound instead of the traditional sensors of older models which are optical and use light.
You can register up to 3 fingerprints on the Galaxy S21 series. This can go as high as 4 fingerprints if you have the 5G variant.
Depending on its thickness and quality, the screen protector can mess up with the Galaxy S21’s display causing the fingerprint sensor to not work as intended. This is why you should only use Samsung-accredited screen protectors.
