How To Fix A Sluggish Galaxy S21 (Android 11, One UI 3)

In this troubleshooting guide, we will show you how to fix a sluggish Galaxy S21 and how to prevent such a problem from happening again in the future. It seems like many users have encountered this problem, and if you’re one of them, continue reading as we may be able to help. 

Performance issues may oftentimes seem so annoying as they occur when you least expect them. However, they’re actually easy to fix, especially if they just manifest without apparent reason. If you are one of the users with this problem, then here’s what you should do: 

First solution: Close all background apps

Performance problems can sometimes be caused by some apps that may have stopped working. That’s why the first thing that you have to do is to close all the applications that are left running in the background and see if the problem gets fixed. Here’s how you do that: 

  1. Tap the Recent Apps key to view the apps that are still running. 
  2. Tap Close All to force quit them in one go. 

After that, try to see if your phone is still sluggish or if the problem is fixed. 

Second solution: Force restart your phone

The first solution may not be enough to fix the problem, so after closing the apps, it’s better to also refresh the memory of your device, as well as reload all the services. You can do both by doing the Forced restart. Here’s how it’s done: 

  1. Press and hold the Volume Down button and the Power key for 10 seconds. This will trigger your phone to shut down and power back up. 
  2. Once the logo shows, release both keys and allow the phone to finish the boot process. 

After the reboot, observe your phone closely to know if your phone is now running smoothly. 

Third solution: Run your device in Safe mode

There is a possibility that the sluggishness you’re currently experiencing is due to some third-party apps and services. You need to rule this possibility out before you can proceed with the other troubleshooting procedures. So run your phone in safe mode and see if the problem doesn’t occur. Here’s how: 

  1. Press and hold the Volume Down button and the Power key for a couple of seconds or until the Power menu shows.
  2. Tap and hold the Power off option until it turns into Safe mode. 
  3. Tap Safe mode to restart your phone. 

While your Galaxy S21 is in safe mode, try to see if the sluggishness is gone. If so, then you have to find out which of the apps you installed is causing the problem, and then reinstall the app. However, if your phone is still sluggish even in this mode, then move on to the next solution. 

Fourth solution: Reset the settings of your device

Performance issues can also be due to some inappropriate settings. Sometimes you may encounter them after changing something on your device. So to rule this possibility out, what you need to do next is to reset all settings on your phone. Here’s how it’s done: 

  1. Open the Settings app on your phone. 
  2. Scroll down and tap General management. 
  3. Tap Reset to view the reset options. 
  4. Tap Reset all settings.
  5. Tap Reset settings to proceed. 
  6. If prompted, enter your security lock. 
  7. Tap Reset to reset the settings of your Galaxy S21. 

After resetting the settings, try to see if your Galaxy S21 is still sluggish. If it still does, then move on to the next solution. 

Fifth solution: Factory reset your phone

Any performance-related problem can be fixed with a factory reset, that’s why if the issue continues to bug you even after doing the previous solutions, then you have no other choice but to do it. However, before you reset your phone, make sure to backup your important files and data because they will be deleted. 

Once you’re ready, follow these steps to reset your device: 

  1. Open the Settings app. 
  2. Scroll down and tap General management. 
  3. Tap Reset to view all reset options. 
  4. Tap Factory data reset.
  5. Scroll down and tap Reset. 
  6. If prompted, enter your security lock. 
  7. Tap Delete all. 
  8. Enter your password and tap Done to proceed with the reset. 

After the reset, set up your phone as a new device. It should be running smoothly now that you’ve already reset it. 

And that’s how you fix a sluggish Galaxy S21. We hope that this troubleshooting guide can help you one way or the other. 

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Harold Hisona

Harold has been in the tech industry since 2008 when he started out as a tech support for companies like Time Warner, Comcast and Tracfone. He’s been troubleshooting phones when the smartphone industry started booming. During his tenure as a tech support, he’s already been writing for various tech blogs and doing some freelance SEO. In 2012, he joined a small team of bloggers to write for The Droid Guy, and he has been with the company ever since. Today, he doesn’t only write tutorials and troubleshooting pieces but also shoots and edits videos for The Droid Guy channel while trading stocks on the side. Contact me at Email

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