How to fix Galaxy Note9 that randomly reboots after Android 9 Pie update

Some Galaxy Note9 users have reported having trouble with their device rebooting randomly after  Android 9 Pie update. This short guide should walk you through the steps on how to fix this problem.

Before we proceed, we want to remind you that if you are looking for solutions to your own #Android issue, you can contact us by using the link provided at the bottom of this page. When describing your issue, please be as detailed as possible so we can easily pinpoint a relevant solution. If you can, kindly include the exact error messages you are getting to give us an idea where to start. If you have already tried some troubleshooting steps before emailing us, make sure to mention them so we can skip them in our answers.

How to fix Galaxy Note9 that randomly reboots after Android 9 Pie update

Below are the troubleshooting steps that you should do when faced with this problem after Android 9 Pie update.

Refresh the system cache. Updates can sometimes corrupt a special set of temporary files called system cache. This usually occurs if the old cache is partially updated, or when the new cache can’t be fully integrated into the old one. If an Android device uses a corrupted or outdated system cache, it may encounter errors or slow down significantly when loading apps. In extreme cases, a device may perform poorly or reboots prematurely. To ensure that your Android has a good system cache, try clearing the cache partition. Here’s how:

  1. Turn off the device.
  2. Press and hold the Volume Up key and the Bixby key, then press and hold the Power key.
  3. When the green Android logo displays, release all keys (‘Installing system update’ will show for about 30 – 60 seconds before showing the Android system recovery menu options).
  4. Press the Volume down key several times to highlight ‘wipe cache partition’.
  5. Press Power button to select.
  6. Press the Volume down key until ‘yes’ is highlighted and press the Power button.
  7. When the wipe cache partition is complete, “Reboot system now” is highlighted.
  8. Press the Power key to restart the device.

Observe on Safe Mode. Sometimes, a bad third party app may cause a problem due to reasons mentioned above. If you recently installed an app, try to see if deleting it will fix the issues. If not, go ahead and check if there’s another one that may be to blame. To do that, you want to boot the phone to safe mode. In this mode, all third party apps will be suspended and will no longer be able to run. If the problems won’t occur while your Note9 is on safe mode, you can bet a third party app is to blame. Here’s how to run your Note9 to safe mode:

  1. Turn the device off.
  2. Press and hold the Power key past the model name screen.
  3. When “SAMSUNG” appears on the screen, release the Power key.
  4. Immediately after releasing the Power key, press and hold the Volume down key.
  5. Continue to hold the Volume down key until the device finishes restarting.
  6. Safe mode will display in the bottom left corner of the screen.
  7. Release the Volume down key when you see Safe Mode.

Don’t forget: safe mode blocks third party apps. If none of the problems you mention are present, then that’s an indicator of a third party app problem. All apps you added after initially setting up the phone are considered third party, even if they products of Google or Samsung. Try to factor them in in your troubleshooting.

Now, if you suspect that a third party app is to blame after doing the safe mode procedure, you should go ahead and narrow down the suspected apps. Here’s how:

  1. Boot to safe mode.
  2. Check for the problem.
  3. Once you’ve confirmed that a third party app is to blame, you can start uninstalling apps individually. We suggest that you begin with the most recent ones you added.
  4. After you uninstall an app, restart the phone to normal mode and check for the problem.
  5. If your Note9 is still problematic, repeat steps 1-4.

Check for overheating. One of the reasons why an Android may reboot randomly is overheating. It can be the underlying issue, or a sign of something deeper. Overheating can be due to a software bug or hardware malfunction. If your device is overheating or if its internal temperature reaches a certain level, it may shut down or restart to avoid damage. If you noticed that your phone becomes uncomfortably warm before shutting down, it must be overheating. That means that there may be an issue with an app, software (Android), or hardware.

Wipe the phone (factory reset). If your phone is overheating, or if you suspect that there’s a software bug causing it to shut down on its own, consider reverting the phone’s software to its defaults. If you can, make sure to create a backup of your personal data first before wiping the device. Once you’ve done that, go ahead and factory reset the phone. Here’s how:

  1. Create a backup of your data.
  2. Turn off the device. This is important. If you can’t turn it off, you’ll never be able to boot to Recovery Mode. If you are not able to shut the device off regularly via the Power button, wait until the phone’s battery is drained. Then, charge the phone for 30 minutes before booting to Recovery Mode.
  3. Press and hold the Volume Up key and the Bixby key, then press and hold the Power key.
  4. When the green Android logo displays, release all keys (‘Installing system update’ will show for about 30 – 60 seconds before showing the Android system recovery menu options).
  5. Press the Volume down key several times to highlight ‘wipe data / factory reset’.
  6. Press Power button to select.
  7. Press the Volume down key until ‘Yes — delete all user data’ is highlighted.
  8. Press Power button to select and start the master reset.
  9. When the master reset is complete, ‘Reboot system now’ is highlighted.
  10. Press the Power key to restart the device.

Have your phone repaired. If your Note9 still reboots randomly on its own after wiping it, you can assume the problem is beyond your ability to fix. Contact Samsung and have the hardware examined. The device may need repair or replacement.

 


Engage with us

If you are one of the users who encounters a problem with your device, let us know. We offer solutions for Android-related problems for free so if you have an issue with your Android device, simply fill in the short questionnaire in this link and we will try to publish our answers in the next posts. We cannot guarantee a quick response so if your issue is time sensitive, please find another way to resolve your problem.

If you find this post helpful, please help us by spreading the word to your friends. TheDroidGuy has social network presence as well so you may want to interact with our community in our Facebook and Google+ pages.